Process for the preparation of cyclic depsipeptides

ABSTRACT

Processes for preparing compounds of Formula (1) and Formula (2) are described, wherein X, Y, Z, R 1 -R 7 , L and n are defined herein. Intermediates useful in the preparation of the compounds of Formula (1) and Formula (2) are also described.

BACKGROUND OF THE INVENTION

The invention relates to the preparation of substituted, cyclicdepsipeptides and to intermediates useful in their preparation. Thecyclic depsipeptides prepared as described herein are disclosed inWO/2011/150283, which is incorporated by reference in its entirety.

The cyclic depsipeptides prepared in accord with the present inventionare known to be histone deacetylase (HDAC) inhibitors as disclosed in,for example, U.S. 20130203681 and are known to be useful in thetreatment of diseases mediated by HDAC disregulation, such as cancer,inflammatory diseases, autoimmune diseases, allergic diseases anddiseases of the central nervous system.

SUMMARY OF THE INVENTION

An aspect of the present invention relates to a process of preparing acompound of the Formula (1)

-   -   or a pharmaceutically acceptable salt thereof,    -   wherein:    -   X, Y and Z are independently carbon or nitrogen, or        alternatively, Y is a direct bond and X and Z are independently        carbon, nitrogen, oxygen or sulfur;    -   R₁ and R₂ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₁ and R₂ taken        together form a C₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl        wherein the C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇        heterocycloalkyl are optionally substituted with one or more        substituents selected from the group consisting of C₁-C₁₀ alkyl,        C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl, heteroaryl,        halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀        alkyl, —O-aryl, —O— heteroaryl, —NR₈R₉, —NR₈C(O)R₉, NR₈C(O)OR₉,        —NR₈CO₂R₉, and —C(O)NR₈R₉;    -   R₃ and R₄ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₃ and R₄ taken        together form a C₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl        wherein the C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇        heterocycloalkyl are optionally substituted with one or more        substituents selected from the group consisting of C₁-C₁₀ alkyl,        C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl, heteroaryl,        halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀        alkyl, —O-aryl, —O-heteroaryl, —NR₈R₉, —NR₈C(O)R₉, NR₈C(O)OR₉,        —NR₈CO₂R₉, and —C(O)NR₈R₉;    -   R₅ and R₆ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₅ and R₆ taken        together form a C₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl        wherein the C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇        heterocycloalkyl are optionally substituted with one or more        substituents selected from the group consisting of C₁-C₁₀ alkyl,        C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl, heteroaryl,        halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀        alkyl, —O-aryl, —O-heteroaryl, —NR₈R₉, —NR₈C(O)R₉, NR₈C(O)OR₉,        —NR₈CO₂R₉ and —C(O)NR₈R₉;    -   R₇ is independently selected from the group consisting of H,        C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl        wherein the C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇        heterocycloalkyl are optionally substituted with one or more        substituents selected from the group consisting of C₁-C₁₀ alkyl,        C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl, heteroaryl,        halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀        alkyl, —O-aryl, —O-heteroaryl, —NR₈R₉, —NR₈C(O)R₉, NR₈C(O)OR₉,        —NR₈CO₂R₉ and —C(O)NR₈R₉;    -   R₈ and R₉ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₈ and R₉ taken        together form a C₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl        wherein the C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇        heterocycloalkyl are optionally substituted with one or more        substituents selected from the group consisting C₁-C₁₀ alkyl,        C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl, heteroaryl,        halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀        alkyl, —O-aryl, —O-heteroaryl, —NR₁₀R₁₁, —NR₁₀C(O)R₁₁,        —NR₁₀C(O)OR₁₁ and —C(O)NR₁₀R₁₁;    -   R₁₀ and R₁₁ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₁₀ and R₁₁ taken        together form a C₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl;    -   L is Cl or SR₁₂;    -   R₁₂ is independently selected from the group consisting of H,        triphenylmethyl, C(O)R₃, CO₂R₁₃, C(O)NR₁₃R₁₄,        C(O)CR₁₃R₁₄NR₁₃R₁₄, amino acid, P(O)(OR₁₅)₂ and SR₁₆;    -   R₁₃ and R₁₄ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl,        aryl and heteroaryl, or R₁₃ and R₁₄ taken together form a C₃-C₇        cycloalkyl or C₃-C₇ heterocycloalkyl wherein the C₁-C₁₀ alkyl,        C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl are optionally        substituted with one or more substituents selected from the        group consisting of C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, C₃-C₇        heterocycloalkyl, aryl, heteroaryl, halo, hydroxyl, —CN, —COOH,        —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀ alkyl, —O-aryl, —O-heteroaryl,        —NR₁₀R₁₁ and —NR₁₀C(O)R₁₁, wherein R₁₀ and R₁₁ are defined as        above;    -   R₁₅ is tert-butyl or —(CH₂)₂Si(CH₃)₃;    -   R₁₆ is C₁-C₁₀ alkyl or C₃-C₇ cycloalkyl;    -   n is 2 or 3, comprising:        -   converting alcohol (VI-A)

wherein TDx is a chiral auxiliary,to carbamate (VIII-A)

wherein R₁₈ is selected from the group consisting of —CH₂CH₂Si(CH₃)₃,(9-fluoren-9-yl)methyl and tert-butyl; and n, R₅, R₆ and TDx are definedas above;

by reaction of alcohol (VI-A) with protected amino acid (VII)

wherein R₅, R₆ and R₁₈ are as defined above, followed by

reacting carbamate (VIII-A) with heterocyclic compound (IX)

wherein R₁₉ is selected from the group consisting of —CH₂CH₂Si(CH₃)₃,(9H-fluoren-9-yl)methyl and tert-butyl; and n, X, Y and Z are as definedabove, to provide compound (X-A)

wherein n, R₁, R₂, R₅, R₆, R₇, R₁₈, R₁₉, X, Y and Z are as definedabove, followed by

selectively removing the carbamate protecting group from compound (X-A)to provide amine (XVII-A)

wherein n, R₁, R₂, R₅, R₆, R₇, R₁₉, X, Y and Z are as defined above,followed by

reacting compound (XVII-A) with protected amino acid (VII-A)

wherein R₃, R₄ and R₁₈ are as defined above;to provide amide (XVIII-A)

wherein n, R₁ to R₇, R₁₈, R₁₉, X, Y and Z are as defined above, followedby

deprotecting amide (XVIII-A) to compound (XIX-A)

wherein n, R₁ to R₇, X, Y and Z are as defined above, followed by

ring closure to compound (XX-A)

wherein n, R₁ to R₇, X, Y and Z are as defined above, followed by

reacting (XX-A) with R₁₂—SH to provide a compound of Formula (1).

In an aspect of the invention,

is a thiazole or an oxazole.

In an aspect of the invention, R₅ is H and R₆ is selected from the groupconsisting of H, isopropyl and methyl.

In an aspect of the invention, R₅ is H and R₆ is isopropyl.

In an aspect of the invention, R₁₂ is C(O)C₇alkyl.

In an aspect of the invention, R₁₂ is C(O)(CH₂)₆CH₃.

In an aspect of the invention, R₃ and R₄ are methyl.

In an aspect of the invention, the compound of Formula (1) is

In an aspect of the invention, the compound of Formula (1) is

In an aspect of the invention, R₁₂ is C(O)CR₁₃R₁₄NR₁₃R₁₄.

An aspect of the present invention relates to a process of preparing acompound of the Formula (2)

or a pharmaceutically acceptable salt thereof,wherein:X, Y and Z are independently carbon or nitrogen, or alternatively, Y isa direct bond andX and Z are independently carbon, nitrogen, oxygen or sulfur;R₁ and R₂ are independently selected from the group consisting of H,C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₁ and R₂ taken together form aC₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl wherein the C₁-C₁₀ alkyl,C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl are optionally substitutedwith one or more substituents selected from the group consisting ofC₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl,heteroaryl, halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀alkyl, —O-aryl, —O-heteroaryl, —NR₈R₉, —NR₈C(O)R₉, —NR₈C(O)OR₉,—NR₈CO₂R₉, and —C(O)NR₈R₉;R₃ is selected from the group consisting of H, C₁-C₁₀ alkyl and C₃-C₇cycloalkyl, or R₃ and R₄ taken together form a C₃-C₇ cycloalkyl or C₃-C₇heterocycloalkyl wherein the C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇heterocycloalkyl are optionally substituted with one or moresubstituents selected from the group consisting of C₁-C₁₀ alkyl, C₃-C₇cycloalkyl, C₃-C₇ heterocycloalkyl, aryl, heteroaryl, halo, hydroxyl,—CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀ alkyl, —O-aryl,—O-heteroaryl, —NR₈R₉, —NR₈C(O)R₉, NR₈C(O)OR₉, —NR₈CO₂R₉, and—C(O)NR₈R₉;R₅ and R₆ are independently selected from the group consisting of H,C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₅ and R₆ taken together form aC₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl wherein the C₁-C₁₀ alkyl,C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl are optionally substitutedwith one or more substituents selected from the group consisting ofC₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl,heteroaryl, halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀alkyl, —O-aryl, —O-heteroaryl, —NR₈R₉, —NR₈C(O)R₉, —NR₈C(O)OR₉,—NR₈CO₂R₉ and —C(O)NR₈R₉;R₇ is independently selected from the group consisting of H, C₁-C₁₀alkyl, C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl wherein the C₁-C₁₀alkyl, C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl are optionallysubstituted with one or more substituents selected from the groupconsisting of C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl,aryl, heteroaryl, halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂,—OC₁—C₁₀ alkyl, —O-aryl, —O-heteroaryl, —NR₈R₉, —NR₈C(O)R₉, NR₈C(O)OR₉,—NR₈CO₂R₉ and —C(O)NR₈R₉;R₈ and R₉ are independently selected from the group consisting of H,C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₈ and R₉ taken together form aC₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl wherein the C₁-C₁₀ alkyl,C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl are optionally substitutedwith one or more substituents selected from the group consisting C₁-C₁₀alkyl, C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl, aryl, heteroaryl, halo,hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂, —OC₁—C₁₀ alkyl, —O-aryl,—O-heteroaryl, —NR₁₀R₁₁, —NR₁₀C(O)R₁₁, —NR₁₀C(O)OR₁₁ and —C(O)NR₁₀R₁₁;R₁₀ and R₁₁ are independently selected from the group consisting of H,C₁-C₁₀ alkyl and C₃-C₇ cycloalkyl, or R₁₀ and R₁₁ taken together form aC₃-C₇ cycloalkyl or C₃-C₇ heterocycloalkyl; andR₁₃ is selected from the group consisting of C₁-C₁₀ alkyl, C₃-C₇cycloalkyl, C₃-C₇ heterocycloalkyl, aryl and heteroaryl, wherein theC₁-C₁₀ alkyl, C₃-C₇ cycloalkyl and C₃-C₇ heterocycloalkyl are optionallysubstituted with one or more substituents selected from the groupconsisting of C₁-C₁₀ alkyl, C₃-C₇ cycloalkyl, C₃-C₇ heterocycloalkyl,aryl, heteroaryl, halo, hydroxyl, —CN, —COOH, —CF₃, —OCH₂F, —OCHF₂,—OC₁—C₁₀ alkyl, —O-aryl, —O-heteroaryl, —NR₁₀R₁₁ and —NR₁₀C(O)R₁₁,wherein R₁₀ and R₁₁ are defined as above, comprising

reacting carbamate (VIII)

wherein R₁₈ is selected from the group consisting of —CH₂CH₂Si(CH₃)₃,(9H-fluoren-9-yl)methyl and tert-butyl; TDx is a chiral auxiliary; andR₅ and R₆ are defined as above, with heterocyclic compound (XXVI)

wherein R₁, R₂, R₃, R₇, X, Y and Z are as defined above, to providecompound (XXVII)

wherein R₁, R₂, R₃, R₅, R₆, R₇, R₁₈, X, Y and Z are as defined above,followed by

removing the carbamate protecting group from compound (XXVII) to provideamine (XXVIII)

wherein R₁, R₂, R₃, R₅, R₆, R₇, X, Y and Z are as defined above,followed by

ring closure to provide amide (XXIX)

wherein R₁, R₂, R₃, R₅, R₆, R₇, X, Y and Z are as defined above,followed by

reacting (XXIX) with R₁₃—SH (XXI)

wherein R₁₃ is as defined above,to provide a compound of Formula (2).

In an aspect of the invention to prepare a compound of Formula (2),

is a thiazole.

In an aspect of the invention to prepare a compound of Formula (2), R₅is H and R₆ is isopropyl.

In an aspect of the invention to prepare a compound of Formula (2), R₁₃is —(CH₂)₆CH₃.

In an aspect of the invention to prepare a compound of Formula (2), R₁and R₂ are H.

In an aspect of the invention to prepare a compound of Formula (2), thecompound of Formula (2) is

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the chemical structures of largazole and several analogsof largazole.

DETAILED DESCRIPTION

A “moiety” or “group” is any type of molecular arrangement designated byformula, chemical name, or structure. Within the context of certainembodiments, a conjugate is said to comprise one or more moieties orchemical groups. This means that the formula of the moiety issubstituted at some place in order to be joined and be a part of themolecular arrangement of the conjugate. Although moieties may bedirectly covalently joined, it is not intended that the joining of twoor more moieties must be directly to each other. A linking group,crosslinking group, or joining group refers to any molecular arrangementthat will connect the moieties by covalent bonds such as, but notlimited to, one or more amide group(s), which may join the moieties.Additionally, although the conjugate may be unsubstituted, the conjugatemay have a variety of additional substituents connected to the linkinggroups and/or connected to the moieties.

A “polymer” or “polymer group” refers to a chemical species or groupmade up of repeatedly linked moieties. Within certain embodiments, it ispreferred that the number of repeating moieties is three or more orgreater than 10. The linked moieties may be identical in structure ormay have variation of moiety structure. A “monomeric polymer” or“homopolymer” is a polymer that contains the same repeating, asymmetricsubunit. A “copolymer” is a polymer that is derived from two or moretypes of monomeric species, i.e., two or more different chemicalasymmetric subunits. “Block copolymers” are polymers comprised of two ormore species of polymer subunits linked by covalent bonds.

The term “substituted”, as used herein, refers to the replacement of atleast one hydrogen atom of a molecular arrangement with a substituent.In the case of an oxo substituent (“═O”), two hydrogen atoms arereplaced. When substituted, one or more of the groups below are“substituents.” Substituents include, but are not limited to, halogen,hydroxy, oxo, cyano, nitro, amino, alkylamino, dialkylamino, alkyl,alkoxy, alkylthio, haloalkyl, aryl, arylalkyl, heteroaryl,heteroarylalkyl, heterocyclyl, and heterocyclealkyl, as well as, —NRaRb,—NRaC(O)Rb, —NRaC(O)NRaNRb, —NRaC(═O)ORb, —NRaSO₂Rb, —C(═O)Ra,—C(═O)ORa, —C(═O)NRaRb, —OC(═O)NRaRb, —ORa, —SRa, —SORa, —S(═O)₂Ra,—OS(═O)₂Ra and —S(═O)ORa. In addition, the above substituents may befurther substituted with one or more of the above substituents, suchthat the substituent comprises a substituted alkyl, substituted aryl,substituted arylalkyl, substituted heterocycle, or substitutedheterocycloalkyl. Ra and Rb in this context may be the same or differentand, independently, hydrogen, alkyl, haloalkyl, substituted alkyl, aryl,substituted aryl, arylalkyl, substituted arylalkyl, heterocyclyl,substituted heterocyclyl, heterocycloalkyl or substitutedheterocycloalkyl.

The term “unsubstituted”, as used herein, refers to any compound thatdoes not contain extra substituents attached to the compound. Anunsubstituted compound refers to the chemical makeup of the compoundwithout extra substituents, e.g., the compound does not containprotecting group(s). For example, unsubstituted proline is a prolineamino acid even though the amino group of proline may be considereddisubstituted with alkyl groups.

The term “alkyl”, as used herein, refers to any straight chain orbranched, non-cyclic or cyclic, unsaturated or saturated aliphatichydrocarbon containing from 1 to 10 carbon atoms, while the term “loweralkyl” has the same meaning as alkyl but contains from 1 to 6 carbonatoms. The term “higher alkyl” has the same meaning as alkyl butcontains from 7 to 10 carbon atoms. Representative saturated straightchain alkyls include, but are not limited to, methyl, ethyl, n-propyl,n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and the like;while saturated branched alkyls include, but are not limited to,isopropyl, sec-butyl, isobutyl, tert-butyl, isopentyl, and the like.Cyclic alkyls may be obtained by joining two alkyl groups bound to thesame atom or by joining two alkyl groups each bound to adjoining atoms.Representative saturated cyclic alkyls include, but are not limited to,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like; whileunsaturated cyclic alkyls include, but are not limited to, cyclopentenyland cyclohexenyl, and the like. Cyclic alkyls are also referred toherein as a “homocycles” or “homocyclic rings.” Unsaturated alkylscontain at least one double or triple bond between adjacent carbon atoms(referred to as an “alkenyl” or “alkynyl”, respectively). Representativestraight chain and branched alkenyls include, but are not limited to,ethylenyl, propylenyl, 1-butenyl, 2-butenyl, isobutylenyl, 1-pentenyl,2-pentenyl, 3-methyl-1-butenyl, 2-methyl-2-butenyl,2,3-dimethyl-2-butenyl, and the like; while representative straightchain and branched alkynyls include, but are not limited to, acetylenyl,propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2-pentynyl,3-methyl-1-butynyl, and the like.

The term “aryl”, as used herein, refers to any aromatic carbocyclicmoiety such as, but not limited to, phenyl or naphthyl.

The term “arylalkyl”, or “aralkyl” as used herein, refers to any alkylhaving at least one alkyl hydrogen atom replaced with an aryl moiety,such as, but not limited to, benzyl, —(CH₂)₂-phenyl, —(CH₂)₃-phenyl,—CH(phenyl)₂, and the like.

The term “halogen”, as used herein, refers to any fluoro, chloro, bromo,or iodo moiety.

The term “haloalkyl”, as used herein, refers to any alkyl having atleast one hydrogen atom replaced with halogen, such as trifluoromethyl,and the like.

The term “heteroaryl”, as used herein, refers to any aromaticheterocycle ring of 5 to 10 members and having at least one heteroatomselected from nitrogen, oxygen and sulfur, and containing at least 1carbon atom, including, but not limited to, both mono and bicyclic ringsystems. Representative heteroaryls include, but are not limited to,furyl, benzofuranyl, thiophenyl, benzothiophenyl, pyrrolyl, indolyl,isoindolyl, azaindolyl, pyridyl, quinolinyl, isoquinolinyl, oxazolyl,isooxazolyl, benzoxazolyl, pyrazolyl, imidazolyl, benzimidazolyl,thiazolyl, benzothiazolyl, isothiazolyl, pyridazinyl, pyrimidinyl,pyrazinyl, triazinyl, cinnolinyl, phthalazinyl, or quinazolinyl.

The term “heteroarylalkyl”, as used herein, refers to any alkyl havingat least one alkyl hydrogen atom replaced with a heteroaryl moiety, suchas —CHpyridinyl, —CH₂pyrimidinyl, and the like.

The term “heterocycle” or “heterocyclic ring”, as used herein, refers toany 4- to 7-membered monocyclic, or 7- to 10-membered bicyclic,heterocyclic ring which is either saturated, unsaturated, or aromatic,and which contains from 1 to 4 heteroatoms independently selected fromnitrogen, oxygen and sulfur, and wherein the nitrogen and sulfurheteroatoms may be optionally oxidized, and the nitrogen heteroatom maybe optionally quaternized, including bicyclic rings in which any of theabove heterocycles are fused to a benzene ring. The heterocycle may beattached via any heteroatom or carbon atom. Heterocycles may includeheteroaryls exemplified by those defined above. Thus, in addition to theheteroaryls listed above, heterocycles may also include, but are notlimited to, morpholinyl, pyrrolidinonyl, pyrrolidinyl, piperidinyl,hydantoinyl, valerolactamyl, oxiranyl, oxetanyl, tetrahydrofuranyl,tetrahydropyranyl, tetrahydropyridinyl, tetrahydroprimidinyl,tetrahydrothiophenyl, tetrahydrothiopyranyl, tetrahydropyrimidinyl,tetrahydrothiophenyl, tetrahydrothiopyranyl, and the like.

The term “heterocycloalkyl”, as used herein, refers to any alkyl havingat least one alkyl hydrogen atom replaced with a heterocycle, such as—CH₂-morpholinyl, and the like.

The term “homocycle” or “cycloalkyl”, as used herein, refers to anysaturated or unsaturated (but not aromatic) carbocyclic ring containingfrom 3-7 carbon atoms, such as, but not limited to, cyclopropane,cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclohexene, andthe like.

The term “alkylamino”, as used herein, refers to at least one alkylmoiety attached through a nitrogen bridge (e.g., —N-alkyl or—N-(alkyl)-N—) including, but not limited to, methylamino, ethylamino,dimethylamino, diethylamino, and the like.

The term “alkyloxy” or “alkoxy”, as used herein, refers to any alkylmoiety attached through an oxygen bridge (e.g., —O-alkyl) such as, butnot limited to, methoxy, ethoxy, and the like.

The term “alkylthio”, as used herein, refers to any alkyl moietyattached through a sulfur bridge (e.g., —S-alkyl) such as, but notlimited to, methylthio, ethylthio, and the like.

The term “alkenyl” refers to an unbranched or branched hydrocarbon chainhaving one or more double bonds therein. The double bond of an alkenylgroup can be unconjugated or conjugated to another unsaturated group.Suitable alkenyl groups include, but are not limited to vinyl, allyl,butenyl, pentenyl, hexenyl, butadienyl, pentadienyl, hexadienyl,2-ethylhexenyl, 2-propyl-2-butenyl,4-(2-methyl-3-butene)-pentenyl. Analkenyl group can be unsubstituted or substituted with one or twosuitable substituents.

The term “alkynyl” refers to unbranched or branched hydrocarbon chainhaving one or more triple bonds therein. The triple bond of an alkynylgroup can be unconjugated or conjugated to another unsaturated group.Suitable alkynyl groups include, but are not limited to ethynyl,propynyl, butynyl, pentynyl, hexynyl, methylpropynyl,4-methyl-1-butynyl, 4-propyl-2-pentynyl-, and 4-butyl-2-hexynyl. Analkynyl group can be unsubstituted or substituted with one or twosuitable substituents.

The term “salts”, as used herein, refers to any salt, such as apharmaceutically acceptable salt, that complexes with identifiedcompounds contained herein. Examples of such salts include, but are notlimited to, acid addition salts formed with inorganic acids (e.g.,hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid,nitric acid, and the like), and salts formed with organic acids such as,but not limited to, acetic acid, oxalic acid, tartaric acid, succinicacid, malic acid, fumaric acid, maleic acid, ascorbic acid, benzoicacid, tannic acid, pamoic acid, alginic acid, polyglutamic, acid,naphthalene sulfonic acid, naphthalene disulfonic acid, andpolygalacturonic acid. Salt compounds can also be administered aspharmaceutically acceptable quaternary salts known by a person skilledin the art, which specifically include the quaternary ammonium salts ofthe formula —NR,R′,R″⁺Z, wherein each R, R′, R″ is independentlyhydrogen, alkyl, or benzyl, and Z is a counter ion, including, but notlimited to, chloride, bromide, iodide, alkoxide, toluenesulfonate,methylsulfonate, sulfonate, phosphate, or carboxylate (such as benzoate,succinate, acetate, glycolate, maleate, malate, fumarate, citrate,tartrate, ascorbate, cinnamoate, mandeloate, and diphenylacetate). Saltcompounds can also be administered as pharmaceutically acceptablepyridine cation salts having a substituted or unsubstituted partialformula: wherein Z is a counter ion, including, but not limited to,chloride, bromide, iodide, alkoxide, toluenesulfonate, methylsulfonate,sulfonate, phosphate, or carboxylate (such as benzoate, succinate,acetate, glycolate, maleate, malate, fumarate, citrate, tartrate,ascorbate, cinnamoate, mandeloate, and diphenylacetate).

As used herein, the term “prodrug” refers to a derivative of a compoundthat can hydrolyze, oxidize, or otherwise react under biologicalconditions (in vitro or in vivo) to provide a compound of the invention.Prodrugs may only become active upon some reaction under biologicalconditions, but they may have activity in their unreacted forms.Examples of prodrugs contemplated herein include, without limitation,analogs or derivatives of compounds of the invention, and/or their saltswhen salt formation is possible, but in particular, derivatives of zincbinding thiol moiety. Examples of prodrug moieties include substitutedand unsubstituted, branched or unbranched lower alkyl ester moieties(e.g., propionic acid esters), lower alkenyl esters, di-loweralkyl-amino lower-alkyl esters (e.g., dimethylaminoethyl ester),acylamino lower alkyl esters (e.g., acetyloxymethyl ester), acyloxylower alkyl esters (e.g., pivaloyloxymethyl ester), aryl esters (phenylester), aryl-lower alkyl esters (e.g., benzyl ester), heteroaryl esters(nicotinate ester), substituted (e.g., with methyl, halo, or methoxysubstituents) aryl and aryl-lower alkyl esters, amides, lower-alkylamides, di-lower alkyl amides, and hydroxy amides. Naturally occurringamino acid esters or their enantiomers, dipeptide esters, phosphateesters, methoxyphosphate esters, disulfides and disulfide dimers.Prodrugs and their uses are well known in the art (see, e.g., Berge etal., Pharmaceutical Salts, J. Pharm. Sci. 66, 1-19 (1977)). Prodrugs cantypically be prepared using well-known methods, such as those describedin Burger's Medicinal Chemistry and Drug Discovery (Manfred E. Wolff ed.(1995)) and (Rautio, Nat. Rev. Drug Discov. 7, 255-270 (2008)).

As used herein, “reactive groups” refer to nucleophiles, electrophiles,or radically active groups, i.e., groups that react in the presence ofradicals. A nucleophile is a moiety that forms a chemical bond to itsreaction partner (the electrophile) by donating both bonding electrons.Electrophiles accept these electrons. Nucleophiles may take part innucleophilic substitution, whereby a nucleophile becomes attracted to afull or partial positive charge on an element and displaces the group itis bonded to. Alternatively nucleophiles may take part in substitutionof carbonyl group. Carboxylic acids are often made electrophilic bycreating succinyl esters and reacting these esters with aminoalkyls toform amides. Other common nucleophilic groups include thiolalkyls,hydroxylalkyls, primary and secondary amines, and carbon nucleophilessuch as enols and alkyl metal complexes. Other preferred methods ofligating proteins, oligosaccharides and cells using reactive groups aredisclosed in (Lemieux and Bertozzi (1998)), incorporated herein byreference. In yet another preferred method, one provides reactive groupsfor the Staudinger ligation, i.e., “click chemistry” with an azidecomprising moiety and alkynyl reactive groups to form triazoles. Michaeladditions of a carbon nucleophile enolate with an electrophiliccarbonyl, or the Schiff base formation of a nucleophilic primary orsecondary amine with an aldehyde or ketone may also be utilized. Othermethods of bioconjugation are provided in (Hang and Bertozzi, J. Am.Chem. Soc. 123, 1242-1243 (2001)) and (Kiick et al. (2002)), both ofwhich are incorporated by reference in their entireties.

The processes of the present invention used to prepare the compounds ofthe present invention, such as those represented by Formula (1) andFormula (2) are illustrated in the following schemes. Unless otherwiseindicated, the variables R₁-R₂₁, X, Y, Z, M, TDx, and n are defined asabove. In particular, the schemes and discussions that follow describethe preparation of the compounds represented by formulae I to XXIX.

The reaction described in Step 1 of Scheme 1 involves a rutheniumcarbene-catalyzed cross olefin metathesis reaction between Compound Iand Compound II to produce Compound III and is performed underconditions that are analogous to those described in Voigtritter, K. etal., J. Org. Chem. 76, 4697-4702 (2011).

In particular, when Compound I was reacted with Compound II (an allylalcohol where R₂₀ is H and R₂₁ is CH₂OH, or R₂₀ and R₂₁ are both CH₂OH)in the presence of a ruthenium carbene catalyst such as, but not limitedto, benzylidene-bis(tricyclohexylphosphine)dichlororuthenium (Grubbsfirst generation catalyst),(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(tricyclohexylphosphine)ruthenium(Grubbs second generation catalyst),(1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxyphenylmethylene)ruthenium(Hoveyda-Grubbs catalyst), or1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene[2-(i-propoxy)-5-(N,N-dimethylaminosulfonyl)phenyl]methyleneruthenium(II) dichloride (Zhan catalyst 1B), in an amount ranging fromabout 0.1 mol % to about 5 mol %, preferably about 0.5 mol %, incombination with copper (I) iodide in an amount ranging from about 1 mol% to about 20 mol %, preferably about 6 mol %, in a solvent such as, butnot limited to, dichloromethane, 1,2-dichloroethane, diethyl ether,methyl tert-butyl ether, diisopropyl ether, di-n-butyl ether,tetrahydrofuran or toluene, preferably dichloromethane, at a temperaturerange of about 0° C. to about 100° C., preferably at room temperature(about 25° C.), Compound III ((E)-5-chloropent-2-en-1-ol), was obtainedand used directly in the next step.

As described in Step 2 of Scheme 1, Compound III((E)-5-chloropent-2-en-1-ol) was oxidized to the corresponding aldehyde,Compound IV ((E)-5-chloropent-2-enal) by treatment with an oxidizingagent such as, but not limited to, manganese (IV) oxide, bariummanganate, 1,1,1-tris(acetyloxy)-1,1-dihydro-1,2-benziodoxol-3-(1H)-one(Dess-Martin periodinane) or catalytic tetrabutylammonium peruthenate(TPAP) combined with a stoichiometric oxidant such as, but not limitedto, sodium periodate, or (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl(TEMPO) combined with a stoichiometric oxidant such as, but not limitedto, sodium hypochlorite or manganese (IV) oxide, preferably manganese(IV) oxide, in a solvent such as, but not limited to, dichloromethane,1,2-dichloroethane or toluene, preferably dichloroethane, at atemperature range of about 0° C. to about 100° C., preferably at roomtemperature (about 25° C.). After filtration (such as through a pad ofCelite™) and solvent evaporation, the product thus obtained was useddirectly in the next step without purification. An analytically puresample of Compound IV was obtained through purification by flash columnchromatography.

In an alternative and preferable method for preparing Compound IV asdepicted in Scheme 2, Compound I was reacted with Compound II (whereinR₂₀ is hydrogen or a lower alkyl group and R₂₁ is CHO, preferablywherein R₂₀ is CH₃ (crotonaldehyde)) in the presence of a rutheniumcarbene catalyst such as, but not limited to,benzylidene-bis(tricyclohexylphosphine)dichlororuthenium (Grubbs firstgeneration catalyst),(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(tricyclohexylphosphine)ruthenium(Grubbs second generation catalyst),(1,3-bis-(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(o-isopropoxyphenylmethylene)ruthenium(Hoveyda-Grubbs catalyst), or1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene[2-(i-propoxy)-5-(N,N-dimethylaminosulfonyl)phenyl]methylene ruthenium(II) dichloride (Zhan catalyst 1), preferably(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(tricyclohexylphosphine)ruthenium(Grubbs second generation catalyst), in an amount ranging from about 0.1mol % to about 5 mol %, preferably about 0.5 mol %, in combination withcopper(I) iodide, in an amount ranging from about 1 mol % to about 20mol %, preferably about 6 mol %, at a temperature of about 0° C. toabout 100° C., preferably at about 40° C. Upon completion, the reactionmixture was cooled and filtered, and the volatile components whichtypically include unreacted 4-chloro-1-pentene, unreacted crotonaldehydeand dichloromethane, were removed by distillation under reduced pressureand heating (such as, but not limited to, about 30° C.). After most ofthe volatile components were removed, the residual product (typicallycontaining small amounts of starting material) was reconstituted(typically in a solvent such as, but not limited to, dichloromethane),and then concentrated again under reduced pressure and heating (such as,but not limited to, about 30° C.) to give (E)-5-chloropent-2-enal asCompound IV, which was used directly in the next step. An analyticallypure sample of Compound IV was obtained through purification by flashcolumn chromatography.

The synthesis of Compound III using the ruthenium carbene-catalyzedcross olefin metathesis reactions described herein, represents asignificant advantage over traditional, more pedestrian synthetic routesinvolving the use of organophosphorous reagents such as(dialkoxyphosphoryl)acetates (“Horner-Wadsworth-Emmonds” reagents) or2-(triphenyl phosphoranylidene)acetaldehyde, which require additionalsynthetic steps and also may result in waste streams that includealuminum and phosphorus oxides. For example, in the present synthesis,the waste stream includes relatively volatile, unreacted startingmaterials (such as 4-chloro-2-pentene and crotonaldehyde) and solventwhich can be distilled from the product and recycled, catalytic amountsof ruthenium species which can be recovered and recycled, manganeseoxides which can be filtered and recycled, and propene gas.

Table 1 below illustrates how conversion rates in the reactionsdescribed in Scheme 1 to prepare Compound III (represented by compound2c) or Compound IV (represented by compound 2a) vary with the choice ofCompound II (represented by compound 1 wherein R₁, R₂ and R₃ have thevalues shown in each of 1a, 1b and 1c), solvent, temperature, additive,catalyst, catalyst loading, and time.

TABLE 1 Catalyst Loading CuI Volume Temp. Conver. Entry Catalyst (mol %)(mol %) 1; (equiv) (Solvent) (Solvent) (° C.) Product (%) 1 CM-1 1 3 1a;2 20 DCM 24 2a 18 2 CM-1 3 3 1a; 5 10 DCM 24 2a 28 3 CM-1 1 3 1b; 2 20DCM 24 2a 65 4 CM-1 1 3 1b; 2 30 DCM 24 2a 70 5 CM-2 1 3 1b; 2 30 DCM 242a 54 6 CM-3 1 3 1b; 2 30 DCM 24 2a 75 7 CM-3 1 6 1b; 1.5 20 DCM 24 2a66 8 CM-3 0.5 6 1b; 1.5 20 DCM 24 2a 62 9 CM-3 0.5 6 1b; 1.5 20 DCM 402a 75 10 CM-3 0.5 6 1b; 1.5 20 THF 40 2a 50 11 CM-3 0.5 6 1b; 1.5 20MTBE 40 2a 56 12 CM-3 0.5 6 1b; 1.5 20 DIE 40 2a 56 13 CM-3 0.5 6 1b;1.5 20 Toluene 40 2a 50 14 CM-3 0.5 6 1c; 1.5 20 DCM 40 2c 82

The synthetic reaction described in Scheme 3 involves an asymmetricaldol reaction (Nagao-Aldol reaction) between the aldehyde of CompoundIV and the thiazolidine thione of Compound V and was carried out underconditions that are analogous to those described in Ren, Q. et al.,Synlett 2008, No. 15, 2379-2383.

The Nagao-Aldol reaction is particularly useful for preparingstereochemically enriched, β-hydroxy carbonyl compounds which do notcontain a substituent other than hydrogen on the carbon alpha to thecarbonyl group bearing the chiral auxiliary. In addition, unlike themore traditional “Evans” chiral oxazolidinone chiral auxiliaries,thiazolidine thione auxiliaries serve to activate the carbonyl groups towhich they are attached towards nucleophilic addition by aminecompounds, in particular primary amines, to give the correspondingamides directly without the need for additional activation. Inparticular, the acetylated chiral auxiliary V of Scheme 3 (where TDxincludes, but is not limited to, (R)-4-isopropylthiazolidine-2-thione,(R)-4-benzylthiazolidine-2-thione, (R)-4-phenylthiazolidine-2-thione or(R)-4-(tert-butyl)thiazolidine-2-thione) was treated with a Lewis acid,a base and the aldehyde of Compound IV to yield Compound VI with a highdegree of diastereoselectivity. Compound IV is substituted with achlorine group in the 5-position which serves a leaving group for theintroduction of a thioester group via a nucleophilic displacementreaction involving the salt of a thioic S-acid as described in SchemesXIII and IX. The Nagao-Aldol reaction has previously been used tosynthesize intermediates related to Compound VI of Scheme 3, which inturn, were employed in the synthesis of the natural product, Largazole.(Taori, K. et al, J. Am. Chem. Soc., (2008), 130, 1806; Leusch, H. etal., Nat. Prod. Rep., (2012), 29, 449). In the majority of the reportedsyntheses, a thiol, protected as its triphenylmethyl derivative, wasused to eventually deliver the thioester group incorporated in thenatural product Largazole and synthetic analogs thereof. (Ying, Y. etal., J. Am. Chem. Soc. (2008), 130, 8457; Bowers, A. et al., J. Am.Chem. Soc., (2008), 130, 11221; Xiao, Q. et al., Journal of AsianNatural Products Research, (2010), 12:11, 940; Benelkebir, H. et al.,Bioorg. Med. Chem. (2011), 19, 3650; Bhansali, P. et al., J. Med. Chem.(2011), 54, 7453). In addition to masking the thiol as a triphenylmethylthioether, the use of a trialkylsilyl ether has also been reported.(Ren, Q. et al., Synlett (2008), No. 15, 2379-2383). In this case, theprotecting group was incompatible with the planned chemistry, whichnecessitated a protecting group exchange to a disulfide group late inthe synthesis. In other reports, the requisite thioester group wasintroduced in a final step using a cross olefin metathesis reaction.(Nasveschuk, C. G. et al., J., Org. Lett. (2008), 10, 3595; Seiser, T.et al., Angew. Chem. Int. Ed. (2008), 47, 6483; Souto, J. A. et al., J.Med. Chem. (2010), 53, 4654). In these published examples, the chemicalyield described for this transformation was uniformly low and thecatalyst loading was uniformly high. Thus, this particular bondconstruction was not an attractive option for large scale synthesis.

The present invention demonstrates the use of a chlorine atom as a lowmolecular weight, “atom-economical” surrogate for a triphenylmethylthiogroup for preparing depsipeptide derivatives related to Largazole viaCompound VI of Scheme 3 which are prepared via a Nagao-Aldol reactionbetween Compounds IV and V. To prepare the aldol product Compound VI,the N-acylated chiral auxiliary, Compound V, comprising a chiralthiazolidine dione, preferably(R)-1-(4-benzyl-2-thioxothiazolidin-3-yl)ethanone or(R)-1-(4-isopropyl-2-thioxothiazolidin-3-yl)ethanone, is treated with aLewis acid, such as, but not limited to, a titanium (IV) halide,preferably titanium tetrachloride, in an aprotic solvent such as, butnot limited to, dichloromethane, 1,2-dichloroethane or toluene,preferably dichloromethane, at about −78° C. to about 0° C., preferablyabout −5° C., over a period of about 30 minutes followed by a tertiaryamine base such as, but not limited to, triethylamine, (−)-sparteine ordiisopropylethyl amine, preferably diisopropylethyl amine, at atemperature of about −78° C. to about 0° C., preferably about −40° C.with stirring for about two hours at which time the resulting solutionis cooled to about −90° C. to about −40° C., preferably −78° C. and asolution of the aldehyde of Compound IV, in an aprotic solvent such as,but not limited to, dichloromethane, 1,2-dichloroethane or toluene,preferably dichloromethane, is added.

TABLE 2

R X = H; Y = OH (1) X = OH; Y = H (2) Isolated Yield Purification MethodVI-A: (CH₃)₂CH— 9 1 80 column chromotography VI-B: PhCH₂— 5 1 71recrystallization

Scheme 4 describes the synthesis of Compound X. In Step 1, the secondaryhydroxyl group of Compound VI was acylated with a protected amino acidderivative, wherein the protecting group is, for example, tert-butyloxycarbonyl (Boc), (9H-fluoren-9-yl)methyloxy carbonyl (Fmoc), or2-(trimethylsilyl)ethyloxy carbonyl, preferably tert-butyloxy carbonyl.

Step 1 of Scheme 4 describes the ester formation between Compound VI andCompound VII to give Compound VIII where R₁₈ of Compound VII includes,but is not limited to, —CH₂CH₂Si(CH₃)₃, (9H-fluoren-9-yl)methyl (Fmoc)or tert-butyl (Boc), preferably tert-butyl, and was carried out using anactivating agent such as, but not limited to,1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI),dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC),carbonyldiimidazole (CDI), 2,4,6-trichlorobenzoyl chloride, preferably1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI), with anaminopyridine catalyst such as, but not limited to,dimethylaminopyridine or 4-pyrrolidinopyridine, preferably4-dimethyaminopyridine, in about 5 mol % to about 30 mol %, preferablyabout 10 mol % in a solvent such as, but not limited to,dichloromethane, 1,2-dichloroethane, acetonitrile, tetrahydrofuran,toluene, heptane, methyl tert-butyl ether, diisopropyl ether, ethylacetate or isopropyl acetate, dimethyl formamide, dimethyl acetamide orN-methyl pyrroldinone, preferably dichloromethane, at a temperature ofabout 0° C. to about 40° C., preferably at room temperature (about 25°C.).

Step 2 of Scheme 4 is an amide-forming reaction wherein the chiralthiazolidine thione group of Compound VIII serves to activate thecarbonyl to which it is attached towards nucleophilic displacement by aprimary amine as previously discussed. In this reaction, Compound IX isa 5- or 6-membered heterocyclic moiety that contains at least onenitrogen in the heterocyclic ring, with a carboxylate group, suitablyprotected as an ester, attached to the same carbon as the nitrogen atom,and a substituted or unsubstituted methylamino group attached to theother carbon atom to which the nitrogen is attached. Thus, each group,ester and substituted or unsubstituted methyl amino, are situated orthoto a nitrogen atom in the heterocyclic ring, and meta to each other. The5- or 6-membered heterocyclic moiety of Compound IX includes, but is notlimited to, pyridine, pyrimidine, pyrazine, triazine, oxazole, thiazole,oxadiazole, or thiadiazole. In an exemplary embodiment, this moiety isthiazole or tert-butyl 2-(aminomethyl)thiazole-4-carboxylate. Thereaction was typically performed by dissolving Compound VIII of Scheme 4in an aprotic solvent such as, but not limited to, dichloromethane,1,2-dichloroethane, acetonitrile, tetrahydrofuran, toluene, heptane,methyl tert-butyl ether, diisopropyl ether, ethyl acetate or isopropylacetate, dimethyl formamide, dimethyl acetamide or N-methylpyrroldinone, preferably dichloromethane, followed by adding Compound VIand stirring for about 1 hour to about 48 hours, preferably about 24hours, at a temperature of about 0° C. to about 40° C., preferably atroom temperature (about 25° C.).

Scheme 5 describes an alternative and more preferable synthesis ofCompound X. In Step 1 of Scheme 5, the Nagao-Aldol product of CompoundVI, is dissolved in an aprotic

solvent such as, but not limited to, dichloromethane,1,2-dichloroethane, acetonitrile, tetrahydrofuran, toluene, heptane,methyl tert-butyl ether, diisopropyl ether, ethyl acetate, isopropylacetate, dimethyl formamide, dimethyl acetamide or N-methylpyrroldinone, preferably dichloromethane, was treated with Compound IX(where R₁₉ is, for example, tert-butyl or CH₂CH₂Si(CH₃)₃, preferablytert-butyl) and stirred for about 1 hour to about 48 hours, preferablyabout 24 hours, at a temperature of about 0° C. to about 40° C.,preferably at room temperature (about 25° C.). Water was added, theorganic layer was separated, and the aqueous layer was extracted oncewith dichloromethane. The organic layers were combined, washed withbrine and concentrated under vacuum. Trituration with ethyl acetateprovided Compound XI in 70-80% yield. Purification of the mother liquorby column chromatography provided additional Compound XI along with therecovered chiral auxiliary which can be reused to synthesize Compound Vas shown in Table 2.

In Step 2 of Scheme 5, the secondary hydroxyl group of Compound XI wasacylated with the protected amino acid derivative of Compound VII,wherein the protecting group is, for example, tert-butyloxy carbonyl(Boc), (9H-fluoren-9-yl)methyloxy carbonyl (Fmoc) or2-(trimethylsilyl)ethyloxy carbonyl, preferably tert-butyloxy carbonyl,to provide Compound X. The reaction was carried out using an activatingagent, such as, but not limited to, dicyclohexylcarbodiimide (DCC),diisopropylcarbodiimide (DIC) or1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI), preferably1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI), in a solvent suchas, but not limited to, dichloromethane, 1,2-dichloroethane,acetonitrile, tetrahydrofuran, toluene, heptane, methyl tert-butylether, diisopropyl ether, ethyl acetate or isopropyl acetate, dimethylformamide, dimethyl acetamide or N-methyl pyrrolidinone, preferablydichloromethane, with an aminopyridine catalyst such as, but not limitedto, dimethylaminopyridine or 4-pyrrolidinopyridine, preferably4-dimethyaminopyridine, in about 5 mol % to about 30 mol %, preferablyabout 10 mol % at a temperature of about 0° C. to about 40° C.,preferably at room temperature (about 25° C.). Water was added to thereaction mixture and the organic layer was separated and washed oncewith water. The organic layer was dried and concentrated to giveCompound X which was used without further purification.

Scheme 6 describes the preparation of the heterocyclic amino acidderivative of Compound XV which exemplifies Compound IX of Schemes 4 and5. Compound

XII and Compound XIII were combined in a solvent such as, but notlimited to, 1,2-dimethoxyethane (DME), tetrahydrofuran (TF) or1,4-dioxane, preferably 1,2-dimethoxyethane (DME), and a base was addedsuch as, but not limited to, sodium hydrogen carbonate or potassiumhydrogen carbonate, preferably potassium hydrogen carbonate, at atemperature of about −40° C. to about 25° C., preferably about −10° C.After stirring for about 10 min to about 24 hours, preferably about 1hour, a solution of trifluoroacetic anhydride and a base such as, butnot limited to, pyridine, 2-methylpyridine, 2,6-dimethyl pyridine,2,3,5-trimethylpyridine or 2,4,6-trimethylpyridine, preferably2,6-dimethylpyridine, in a solvent such as, but not limited to,1,2-dimethoxyethane (DME), tetrahydrofuran (TIF) or 1,4-dioxane,preferably 1,2-dimethoxyethane, was added at a temperature of about −40°C. to about 25° C., preferably about −20° C. After stirring for about 10min to about 24 hours, preferably about 2 hours, the mixture was pouredinto water and subsequent extractive workup provided Compound XIV as asolid.

In an alternative and preferable method for preparing Compound XV ofScheme 6, Compound XII of Scheme 6 was combined with Compound XIII ofScheme 6 in a solvent such as, but not limited to, methanol, ethanol,isopropanol, sec-butanol, dichloromethane, 1,2-dichloroethane,acetonitrile, tetrahydrofuran, toluene, heptane, methyl tert-butylether, diisopropyl ether, 1,2-dimethoxy ethane, 1,4-dioxane, ethylacetate, isopropyl acetate, dimethyl formamide, dimethyl acetamide orN-methyl pyrroldinone, preferably isopropanol, and stirred at atemperature of about 0° C. to about 100° C., preferably about 25° C., inthe absence of, or in the presence of a base such as, but not limitedto, aqueous sodium hydroxide, aqueous potassium hydroxide, aqueouslithium hydroxide, or calcium carbonate, preferably aqueous sodiumhydroxide, for a period of about 1 hour to about 72 hours, preferablyabout 24 hours. The reaction was diluted with water and Compound XIV wasobtained after subsequent extractive workup.

Scheme 7a describes the selective removal of the carbamate protectinggroup bearing R₁₈ within Compound XVI, in the presence of the estergroup bearing R₁₉, to provide Compound XVII.

Thus, the carbamate protecting group bearing R₁₈ and the ester groupbearing R₁₉ within Compound XVI are orthogonal protecting groups withrespect to their structure or reactivity. R₁₈ of Compound XVI includes,but is not limited to, —CH₂CH₂Si(CH₃)₃, (9H-fluoren-9-yl)methyl (Fmoc)or tert-butyl (Boc). R¹⁹ of Compound XVI includes, but is not limitedto, —CH₂CH₂Si(CH₃)₃ or tert-butyl (Boc). When R₁₈ of Compound XVI is—CH₂CH₂Si(CH₃)₂, Step 1 of Scheme 7a was carried out by treatingCompound XVI with a fluoride source such as, but not limited to,potassium fluoride, cesium fluoride, tetrabutylammonium fluoride orlithium tetrafluoroborate, preferably tetrabutylammonium fluoride in asolvent such as, but not limited to, tetrahydrofuran, acetonitrile,dimethyl formamide, N-methylpyrrolidone, N,N-dimethyl acetamide ordimethyl sulfoxide, preferably tetrahydrofuran, at a temperature ofabout 0° C. to about 65° C., preferably at room temperature (about 25°C.).

When R₁₈ of Compound XVI is (9H-fluoren-9-yl)methyl (Fmoc), Step 1 ofScheme 7a was carried out by treating Compound XVI with an amine basesuch as, but not limited to, morpholine, piperidine, piperazine,1,4-bis-(3-aminopropylpiperazine, dicyclohexylamine, diisopropylethylamine, 4-dimethylminopyridine, 1,8-Diazabicyclo[5.4.0]undec-7-ene,pyrrolidine, cyclohexylamine, ethanolamine, diethylamine, triethylamine,ammonia, tributylamine or triethylenediamine, preferably piperidine, ina solvent such as, but not limited to, dichloromethane,1,2-dichloroethane, dimethyl formamide, n-methylpyrolidinone, orN,N-dimethylacetamide, preferably dichloromethane, at a temperature ofabout −20° C. to about 40° C., preferably at room temperature (about 25°C.).

When R₁₈ of Compound XVI is tert-butyl (Boc), Step 1 of Scheme 7a wascarried out by treating Compound XVI with an acid such as, for example,trifluoroacetic acid or HCl, dissolved in an organic solvent such as,for example, dichloromethane, toluene, ethyl acetate, THF, DME, MTBE, ordioxane, at a temperature of about 0° C. to about 40° C., preferably atroom temperature (about 25° C.). Preferably, R₁₈ of Compound XVI istert-butyl and Step 1 is carried out preferably with HCl in dioxane,more preferably at room temperature (about 25° C.). The reaction mixturewas poured into a cooled, saturated solution of sodium bicarbonate atabout pH 8-9, and the resulting mixture was twice extracted with ethylacetate, once with brine, dried, and concentrated to dryness to provideCompound XVII in about 95% yield, and which was used directly in thenext step without further purification.

In Step 2 of Scheme 7a, Compound XVII was converted to Compound XVIII bytreatment with Compound VII and an activating agent such as, but notlimited to, dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide(DIC) or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI),preferably 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) byitself or in the presence of an additive such as, but not limited to,hydroxybenztriazole (HOBt) or 1-hydroxy, 7-azabenztriazolein, preferablyhydroxybenztriazole (HOBt), in a solvent such as, but not limited to,dichloromethane, 1,2-dichloroethane, acetonitrile, tetrahydrofuran,toluene, heptane, methyl tert-butyl ether, diisopropyl ether, ethylacetate or isopropyl acetate, dimethyl formamide, dimethyl acetamide orN-methyl pyrroldinone, preferably dichloromethane, at a temperature ofabout −20° C. to about 60° C., preferably at room temperature (about 25°C.).

In Step 3 of Scheme 7a, Compound XIX was produced by simultaneoushydrolysis of the carbamate and ester groups bearing R₁₈ and R₁₉respectively, within Compound XVIII. Thus, for example when R₁₈ and R₁₉are both —CH₂CH₂Si(CH₃)₃, Step 3 was carried out by treating CompoundXVIII with, for example, potassium fluoride, cesium fluoride,tetrabutylammonium fluoride, lithium tetrafluoroborate, ortrifluoroacetic acid, preferably tetrabutylammonium fluoride, in asolvent such as, but not limited to, tetrahydrofuran, acetonitrile,dimethyl formamide, N-methylpyrrolidinone, N,N-dimethyl acetamide ordimethyl sulfoxide, preferably tetrahydrofuran, at a temperature ofabout 0° C. to about 40° C., preferably at room temperature (about 25°C.).

Alternatively and preferably, when R₁₈ and R₁₉ are both tert-butyl, Step3 of Scheme 7a was carried out by treating Compound XVIII with an acidsuch as, but not limited to, trifluoroacetic acid or HCl, preferablytrifluoroacetic acid, in a solvent such as, but not limited to,dichloromethane, 1,2-dichloroethane, or toluene, preferablydichloromethane, at a temperature of about 0° C. to about 40° C.,preferably at room temperature (about 25° C.).

Scheme 7b describes the concomitant removal of the carbamate protectinggroup bearing R₁₈ within Compound XVI, and the ester group bearing R₁₉,to provide Compound XVII-A. Preferably, when R₁₈ and R₁₉ are bothtert-butyl, Step 1 of Scheme 7b is carried out by treating Compound XVIwith an acid such as, but not limited to, trifluoroacetic acid or HCl,preferably trifluoroacetic acid, in a solvent such as, but not limitedto, dichloromethane, 1,2-dichloroethane, or toluene, preferablydichloromethane, at a temperature of about 0° C. to about 40° C.,preferably at room temperature (about 25° C.).

In Step 2 of Scheme 7b, Compound XVII-A was converted to CompoundXVIII-A by treatment with Compound VII and an activating agent such as,but not limited to, dicyclohexylcarbodiimide (DCC),diisopropylcarbodiimide (DIC) or1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI), preferably1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) by itself or in thepresence of an additive such as, but not limited to, hydroxybenztriazole(HOBt) or 1-hydroxy, 7-azabenztriazolein, preferably hydroxybenztriazole(HOBt), in a solvent such as, but not limited to, dichloromethane,1,2-dichloroethane, acetonitrile, tetrahydrofuran, toluene, heptane,methyl tert-butyl ether, diisopropyl ether, ethyl acetate or isopropylacetate, dimethyl formamide, dimethyl acetamide or N-methylpyrroldinone, preferably dichloromethane, at a temperature of about −20°C. to about 60° C., preferably at room temperature (about 25° C.).

In Step 3 of Scheme 7b, Compound XIX was produced by hydrolysis of thecarbamate and ester group bearing R₁₈ within Compound XVIII-A. Thus, forexample when R₁₈ is tert-butyl, Step 3 of Scheme 7b was carried out bytreating Compound XVIII-A with an acid such as, but not limited to,trifluoroacetic acid or HCl, preferably trifluoroacetic acid, in asolvent such as, but not limited to, dichloromethane,1,2-dichloroethane, or toluene, preferably dichloromethane, at atemperature of about 0° C. to about 40° C., preferably at roomtemperature (about 25° C.).

Step 1 of Scheme 8 is a macrolactamization reaction whereby the aminogroup of Compound XIX is acylated in an intramolecular fashion by thecarboxylic acid group in

Compound XIX to afford Compound XX. Step 1 was carried out by treatmentof Compound XIX with an activating agent such as, but not limited to,N-[(dimethylamino)-1H-1,2,3-triazolo-[4,5-b]pyridin-1-ylmethylene]-N-methylmethanaminiumhexafluorophosphate N-oxide (HATU),(O-(7-azabenztriazol-1-yl)-1,1,3,3-bis(tetramethylene)uraniumhexafluorophosphate) (HBTU),N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uroniumhexafluorophosphate, O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluroniumhexafluorophosphate, DCC, DIC, EDCI, BDDC, BOP, PyBOP, BOMP, AOP, PyAOP,PyDOP, PyNOP, PyFOP, PyNFOP, NOP, NSBt, N-NSBt, N-HBTU, N-HATU or(HAPyU), preferablyN-[(dimethylamino)-1H-1,2,3-triazolo-[4,5-b]pyridin-1-ylmethylene]-N-methylmethanaminiumhexafluorophosphate N-oxide (HATU), by itself or in or in the presenceof an additive such as, but not limited to, (HOSuc), (HODhbt), (HOt),(HOCt), (Oxama), (6-CF₃—HOBt), (6-NO₂—HOBt), hydroxy-1,2,3-triazole,hydroxybenztriazole (HOBt) or 1-hydroxy-7-azabenztriazolein (HOAt),preferably hydroxybenztriazole (HOBt), in a solvent such as, but notlimited to, dichloromethane, 1,2-dichloroethane, acetonitrile,tetrahydrofuran, toluene, heptane, methyl tert-butyl ether, diisopropylether, ethyl acetate or isopropyl acetate, dimethyl formamide, dimethylacetamide or N-methyl pyrroldinone, preferably a combination ofdichloromethane and dimethylformamide in a ratio of about 20:1 to about1:1, preferably about 10:1, at a concentration of about 5 volumes toabout 50 volumes with respect to Compound XIX, preferably at 10 volumes,at a temperature of about 0° C. to about 40° C., preferably at roomtemperature (about 25° C.).

In Step 2 of Scheme 8, Compound XX was converted to Compound XXII. Thereaction was carried out by treating Compound XX with a thioatenucleophile prepared from the treatment of Compound XXI with a base suchas, but not limited to, potassium hydroxide, sodium hydroxide, lithiumhydroxide, cesium carbonate, potassium carbonate, sodium carbonate,lithium carbonate, potassium hydrogen carbonate, sodium hydrogencarbonate, sodium methoxide, potassium tert-butoxide, triethyl amine,N,N-diisopropylethylamine or 1,8-diazabicyclo[5.4.0]undec-7-ene,preferably potassium carbonate, in a solvent such as, but not limitedto, acetone, acetonitrile, tetrahydrofuran, diisopropyl ether, methyltert-butyl ether, 1,2-dimethoxyethane, 1,4-dioxane, toluene,dichloromethane, 1,2-dichloroethane, ethyl acetate, isopropyl acetate,methanol, ethanol, water, dimethyl formamide, N-methyl pyrrolidinone,N,N,-dimethyl acetamide or dimethyl sulfoxide, preferably acetonitrile,at a temperature of about −10° C. to about 100° C., preferably about 60°C. The thioate intermediate was formed either by itself and then addedto the reaction mixture, or formed in situ, preferably in situ, in theabsence of, or in the presence of sodium iodide or potassium iodide,preferably in the presence of potassium iodide, in an amount of about 5mol % to about 300 mol %, preferably about 100 mol %.

In Step 1 of Scheme 9, Compound XX is converted to Compound XXIV. The

reaction was carried out by treating Compound XX with athioatenucleophile prepared from the treatment of Compound XXIII with abasesuch as, but not limited to, potassium hydroxide, sodium hydroxide,lithium hydroxide, cesium carbonate, potassium carbonate, sodiumcarbonate, lithium carbonate, potassium hydrogen carbonate, sodiumhydrogen carbonate, sodium methoxide, potassium tert-butoxide, triethylamine, N,N-diisopropylethylamine or 1,8-diazabicyclo[5.4.0]undec-7-ene,preferably potassium carbonate, in a solvent such as, but not limitedto, acetone, acetonitrile, tetrahydrofuran, diisopropyl ether, methyltert-butyl ether, 1,2-dimethoxyethane, 1,4-dioxane, toluene,dichloromethane, 1,2-dichloroethane, ethyl acetate, isopropyl acetate,methanol, ethanol, water, dimethyl formamide, N-methyl pyrrolidinone,N,N,-dimethyl acetamide or dimethyl sulfoxide, preferably acetonitrile,at a temperature of about −10° C. to about 100° C., preferably about 60°C. The thioate intermediate was formed either by itself and then addedto the reaction mixture or formed in situ, preferably in situ, in theabsence of, or in the presence of sodium iodide or potassium iodide,preferably in the presence of potassium iodide, in an amount of about 5mol % to about 300 mol %, preferably about 100 mol %.

In Step 2 of Scheme 9, Compound XXIV was converted to Compound XXV. Thereaction was carried out by treating Compound XXIV with an acid.

In addition to having utility in preparation of the therapeutic agentsof Formula (1), Compound VIII of Scheme 10, wherein R¹⁸ is describedabove, is useful in the preparation of Largazole and Largazole analogsdescribed in, for example, U.S. Published Application No. 20100029731 toWilliams et al.

As shown in step 1 of Scheme 10, Compound VIII was treated with CompoundXXVI in a manner analogous to conditions described in Xie et al.,Journal of Asian Nat. Prod. Res. (2010), 12, 940-949 to provide CompoundXXVII.

In step 2 of Scheme 10, Compound XXVII was converted to thecorresponding amino acid via Boc group deprotection to give CompoundXXVIII.

In Step 3 of Scheme 10, Compound XXVIII was converted to Compound XXIXvia a macrolactamization reaction by treatment with an activating agentsuch as, but not limited to,N-[(dimethylamino)-1H-1,2,3-triazolo-[4,5-b]pyridin-1-ylmethylene]-N-methylmethanaminiumhexafluorophosphate N-oxide (HATU),(O-(7-azabenztriazol-1-yl)-1,1,3,3-bis(tetramethylene)uraniumhexafluorophosphate) (HBTU),N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uroniumhexafluorophosphate, O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluroniumhexafluorophosphate, DCC, DIC, EDCI, BDDC, BOP, PyBOP, BOMP, AOP, PyAOP,PyDOP, PyNOP, PyFOP, PyNFOP, NOP, NSBt, N-NSBt, N-HBTU, N-HATU or(HAPyU), preferablyN-[(dimethylamino)-1H-1,2,3-triazolo-[4,5-b]pyridin-1-ylmethylene]-N-methylmethanaminiumhexafluorophosphate N-oxide (HATU), by itself or in or in the presenceof an additive such as, but not limited to, (HOSuc), (HODhbt), (HOt),(HOCt), (Oxama), (6-CF₃—HOBt), (6-NO₂—HOBt), hydroxy-1,2,3-triazole,hydroxybenztriazole (HOBt) or 1-hydroxy-7-azabenztriazolein (HOAt),preferably hydroxybenztriazole (HOBt), in a solvent such as, but notlimited to, dichloromethane, 1,2-dichloroethane, acetonitrile,tetrahydrofuran, toluene, heptane, methyl tert-butyl ether, diisopropylether, ethyl acetate or isopropyl acetate, dimethyl formamide, dimethylacetamide or N-methyl pyrroldinone, preferably a combination ofdichloromethane and dimethylformamide in a ratio of about 20:1 to about1:1, preferably about 10:1, at a concentration of about 5 volumes toabout 50 volumes with respect to Compound XIX, preferably at 10 volumes,at a temperature of about 0° C. to about 40° C., preferably at roomtemperature (about 25° C.).

In step 4 of Scheme 10, Compound XXIX was converted to a compound ofFormula (2). The reaction was carried out by treating Compound XXIX witha thioate nucleophile prepared from the treatment of Compound XXI-A witha base such as, but not limited to, potassium hydroxide, sodiumhydroxide, lithium hydroxide, cesium carbonate, potassium carbonate,sodium carbonate, lithium carbonate, potassium hydrogen carbonate,sodium hydrogen carbonate, sodium methoxide, potassium tert-butoxide,triethyl amine, N,N-diisopropylethylamine or1,8-diazabicyclo[5.4.0]undec-7-ene, preferably potassium carbonate, in asolvent such as, but not limited to, acetone, acetonitrile,tetrahydrofuran, diisopropyl ether, methyl tert-butyl ether,1,2-dimethoxyethane, 1,4-dioxane, toluene, dichloromethane,1,2-dichloroethane, ethyl acetate, isopropyl acetate, methanol, ethanol,water, dimethyl formamide, N-methyl pyrrolidinone, N,N,-dimethylacetamide or dimethyl sulfoxide, preferably acetonitrile, at atemperature of about −10° C. to about 100° C., preferably about 60° C.The thioate intermediate was formed either by itself and then added tothe reaction mixture, or formed in situ, preferably in situ, in theabsence of, or in the presence of sodium iodide or potassium iodide,preferably in the presence of potassium iodide, in an amount of about 5mol % to about 300 mol %, preferably about 100 mol %.

EXAMPLES Example 1: Preparation ofS-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)octanethioate (Compound XXII) from((7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)(Compound XX)

((7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)(1.0g, 2.07 mmol), octanethioic S-acid (0.66 g, 4.13 mmol), potassiumcarbonate (0.57 g, 4.13 mmol) and potassium iodide (0.067 g, 0.41 mmol)were dissolved in acetonitrile (20 mL) at room temperature. The mixturewas stirred at room temperature under nitrogen for 16 hours. The mixturewas filtered, concentrated and purified by flash chromatography onsilica gel (petroleum ether/ethyl acetate/methanol 20/20/1) to give 1.13g, (90%) ofS-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)octanethioate as a tan solid. ¹H NMR: (CDCl₃, 400 MHz): δ 8.02 (s, 1H),7.65 (s, 1H), 6.63 (d, J=9.6 Hz, 1H), 6.46 (m, 1H), 5.79-5.73 (m, 2H),5.60 (m, 1H), 5.15 (dd, J=17.6, 8.2 Hz, 1H), 4.63 (m, 1H), 4.36 (dd,J=17.2, 4.0 Hz, 1H), 2.86 (t, J=7.2 Hz, 2H), 2.71 (m, 2H), 2.51 (t,J=7.6 Hz, 2H), 2.30 (m, 3H), 1.89 (s, 3H), 1.61 (s, 3H), 1.28 (bs, 10H),0.88 (m, 6H), 0.69 (d, J=6.8 Hz, 3H).

Example 2: Preparation of(S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-((tert-butoxycarbonyl)amino)-3-methylbutanethioate (Compound XXIV)from(7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)(CompoundXX) and (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanethioic S-acid(Compound XXIII)

(7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)(15g, 0.031 mmol), (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanethioicS-acid (Boc-(D)Val-SH) (12.5 g, 0.054 mmol), potassium carbonate (11.2g, 0.081), and potassium iodide (0.50 g, 0.003 mmol) were dissolved in10 mL of acetonitrile and the resulting mixture was warmed to 60-65° C.and stirred under nitrogen for 18 hrs. The reaction mixture was cooledto room temperature, water (50 mL) was added, and the resulting mixturewas extracted with ethyl acetate (50 mL) twice. The combined organiclayers were washed with 40 mL of water, dried with anhydrous sodiumsulfate and concentrated and purified by flash chromatography on silicagel (petroleum ether/ethyl acetate 80/20) to give 16.90 g (80%) of(S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-((tert-butoxycarbonyl)amino)-3-methylbutanethioate as a foamy solid.¹H NMR: (CDCl₃, 400 MHz): δ 8.02 (s, 1H), 7.64 (s, 1H), 6.62 (bs, 1H),6.50 (d, J=9.6 Hz, 1H), 5.70-5.69 (m, 3H), 5.18 (dd, J=17.6, 8.0 Hz,1H), 5.06 (d, J=9.6 Hz, 1H), 4.63 (m, 1H), 4.38 (dd, J=9.6 Hz, 6 Hz,1H), 4.24 (dd, J=9.2, 4.8 Hz, 1H), 2.92 (t, J=7.0 Hz, 2H), 2.70-2.65 (m,2H), 2.31 (m, 4H), 2.30 (m, 3H), 1.90 (s, 3H), 1.61 (s, 3H), 1.45 (s,9H), 0.99 (d, J=6.4 Hz, 3H), 0.89 (d, J=7.2 Hz, 3H), 0.86 (d, J=6.8 Hz,3H), 0.69 (d, J=7.2 Hz, 3H).

Example 3a: Preparation of(S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-amino-3-methylbutanethioate hydrochloride (Compound XXV-A) from((S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-((tert-butoxycarbonyl)amino)-3-methylbutanethioate) (Compound XXIV)

((S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-((tert-butoxycarbonyl)amino)-3-methylbutanethioate) (8.0 g, 11.7 mmol)was dissolved in 160 mL dichloromethane and trifluoroacteic acid (24 ml)was added at 10° C. under nitrogen. After the addition, the mixture wasstirred at room temperature for 5 hours at which time it wasconcentrated to dryness. The residue was dissolved in ethyl acetate (50ml), and a solution of HCl in ethyl acetate (10.0 ml, 4.0M) was addedslowly dropwise, and the resulting mixture stirred for 10 minutes afterthe addition was complete. Petroleum ether (50 ml) was then added andthe precipitated solid was collected by filtration and dried undervacuum to afford 6.88 g (95%) of(S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-amino-3-methylbutanethioate hydrochloride as a white solid. ¹H NMR:(DMSO-d₆, 400 MHz): δ 8.55 (bs, 4H), 8.16 (s, 1H), 7.90 (m, 2H), 5.63(m, 3H), 4.97 (dd, J=17.6, 8.2 Hz, 1H), 4.34-4.30 (m, 2H), 4.08 (m, 1H),3.04 (m, 1H), 2.96 (m, 1H), 2.76 (m, 1H), 2.20-2.08 (m, 4H), 1.71 (s,3H), 1.46 (s, 3H), 0.99 (d, J=6.4 Hz, 3H), 0.96 (d, J=6.4 Hz, 3H), 0.78(d, J=6.8 Hz, 3H), 0.57 (d, J=6.8 Hz, 3H).

Example 3b: Preparation of(S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-amino-3-methylbutanethioate benzenesulfonate (Compound XXV-B) from((S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-((tert-butoxycarbonyl)amino)-3-methylbutanethioate) (Compound XXIV)

To a solution of((S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-((tert-butoxycarbonyl)amino)-3-methylbutanethioate) (3.0 g, 4.41 mmol)in 50 mL acetonitrile was added benzenesulfonic acid (2.70 g, 17.10mmol) at room temperature and the resulting mixture was stirred for 5hours at which time it was concentrated to dryness. The residue wassuspended in heptane (100 ml), and stirred for 30 minutes at which timethe heptane was removed by decanting. The oily residue was then treatedwith THF (5 ml) and stirred at room temperature for 16 hrs. to afford1.6 g (50%) of(S)—S-((E)-4-((7S,10S)-7-isopropyl-4,4-dimethyl-2,5,8,12-tetraoxo-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-dien-10-yl)but-3-en-1-yl)2-amino-3-methylbutanethioate benzenesulfonate as a white solid.

Example 4: Preparation of(7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)(Compound XX) from(7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)(Compound XIX)

HATU (26 g, 0.067 mol) was dissolved in acetonitrile (300 mL), andcooled to 0˜5° C. A solution of2-(((S,E)-3-(((S)-2-(2-amino-2-methylpropanamido)-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)thiazole-4-carboxylicacid trifluoroacetate (28 g crude from Example 5) and diisopropylethylamine (40 ml, 0.225 mol) in dichloromethane (600 mL) and was addedslowly dropwise to the HATU solution at 0˜5° C. over 5-6 hours. Afterthe addition, the mixture was stirred at 0˜5° C. for an additional 2hours at which time water (600 ml) was added. After layer separation,the aqueous layer was extracted twice with ethyl acetate (200 mL), andthe combined organic layers were washed with brine, dried with anhydroussodium sulfate and concentrated. Flash chromatography with silica gel(petroleum ether/ethyl acetate 50/50) provided 14.5 g (75% overall fromtert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-11,11,15,15-tetramethyl-3,7,10,13-tetraoxo-6,14-dioxa-2,9,12-triazahexadecyl)thiazole-4-carboxylate)(from Example 5) of(7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)as a white solid. ¹H NMR: (CDCl₃, 400 MHz): δ 8.05 (s, 1H), 7.69 (s,1H), 6.61 (d, J=9.6 Hz, 1H), 6.41 (m, 1H), 5.83-5.73 (m, 3H), 5.19 (dd,J=17.2, 8.0 Hz, 1H), 4.67 (dd, J=9.6, 4.2 Hz, 1H), 4.36 (dd, J=17.6, 4.0Hz, 1H), 3.56 (m, 2H), 2.75 (m, 2H), 2.52 (m, 2H), 2.34 (m, 1H), 1.91(s, 3H), 1.64 (s, 3H), 0.93 (d, J=6.8 Hz, 3H), 0.75 (d, J=6.8 Hz, 3H).

Example 5: Preparation of(7S,10S)-10-((E)-4-chlorobut-1-en-1-yl)-7-isopropyl-4,4-dimethyl-9-oxa-16-thia-3,6,13,18-tetraazabicyclo[13.2.1]octadeca-1(17),15(18)-diene-2,5,8,12-tetraone)(Compound XIX) from2-(((S,E)-3-(((S)-2-(2-amino-2-methylpropanamido)-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)thiazole-4-carboxylicacid trifluoroacetate (Compound XVIII)

Tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-11,11,15,15-tetramethyl-3,7,10,13-tetraoxo-6,14-dioxa-2,9,12-triazahexadecyl)thiazole-4-carboxylate(28 g, 0.04 mol) was dissolved in dichloromethane (300 ml), andtrifluoroacetic acid (150 mL) was added. The mixture was stirred at roomtemperature for 20 hours and then concentrated to dryness. The crude2-(((S,E)-3-(((S)-2-(2-amino-2-methylpropanamido)-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)thiazole-4-carboxylicacid trifluoroacetate thus obtained was used directly in next step(Example 4) without purification.

Example 6: Preparation of tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-11,11,15,15-tetramethyl-3,7,10,13-tetraoxo-6,14-dioxa-2,9,12-triazahexadecyl)thiazole-4-carboxylateacid trifluoroacetate (Compound XVIII) from tert-butyl2-(((S,E)-3-(((S)-2-amino-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)thiazole-4-carboxylate(Compound XVII) and 2-((tert-butoxycarbonyl)amino)-2-methylpropanoicacid (Compound VII)

Tert-butyl2-(((S,E)-3-(((S)-2-amino-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)thiazole-4-carboxylate(20.0 g, 0.045 mol) and 2-((tert-butoxycarbonyl)amino)-2-methylpropanoicacid (8.4 g, 0.010 mol,) were dissolved in dichloromethane (200 mL).HATU (17.6 g, 0.048 mol) and diisopropylethyl amine (12 g, 0.096 mol)were successively added to the solution at 10-15° C. and stirringcontinued for 1 hour. 100 mL water was then added to the reactionmixture. The phases were separated and the aqueous phase was extractedwith 100 mL dichloromethane. The combined organic phases were, driedwith anhydrous sodium sulfate, filtered and concentrated to give 26.7 g(90%) of tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-11,11,15,15-tetramethyl-3,7,10,13-tetraoxo-6,14-dioxa-2,9,12-triazahexadecyl)thiazole-4-carboxylateacid trifluoroacetate which was used without further purification. ¹HNMR: (CDCl₃, 400 MHz): δ 7.99 (s, 1H), 7.34 (bs, 1H), 7.15 (bs, 1H),6.00 (bs, 1H), 5.80 (m, 1H), 5.65 (m, 1H), one extra proton in thisregion, took one proton out 4.94 (s, 1H), 4.75 (d, J=6.0 Hz, 2H), 4.23(t, J=6.7 Hz, 1H), 3.50 (t, J=6.7 Hz, 2H), 2.65 (bs, 2H), 2.48 (q, J=6.7Hz, 2H), 2.11 (m, 1H), 1.58 (s, 9H), 1.48-1.39 (m, 15H), 0.94 (d, J=6.8Hz, 3H), 0.89 (d, J=6.8 Hz, 3H).

Example 7: Preparation of tert-butyl2-(((S,E)-3-(((S)-2-amino-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)thiazole-4-carboxylate(Compound XVII) from tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)thiazole-4-carboxylate(Compound XVI)

To a solution of tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)thiazole-4-carboxylate(27.0 g, 8 mmol) in dioxane (20 mL) at 5-10° C. was added 4M HCl indioxane (20 mL). The mixture was stirred at 5-10° C. for 3 hours andslowly poured into a cooled, saturated sodium carbonate solution. Theresulting mixture was extracted twice with 100 mL of ethyl acetate, andthe combined organic layers were washed with brine, dried with anhydroussodium sulfate and concentrated to give 22.3 g (100%) of tert-butyl2-(((S,E)-3-(((S)-2-amino-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)thiazole-4-carboxylateas a pale yellow oil which was used directly in next step (Example 6)without further purification.

Example 8: Preparation of tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)thiazole-4-carboxylate(Compound VIII) from (S,E)-tert-butyl2-((7-chloro-3-hydroxyhept-4-enamido)methyl)thiazole-4-carboxylate(Compound VI-B) and 2-((tert-butoxycarbonyl)amino)-2-methylpropanoicacid (Compound VII

To solution of(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(2.0 g, 5.4 mmol) in dichloromethane (20 mL) was added(S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (1.41 g; 6.5mmol), dicyclohexylcarbodiimide (1.34 g; 6.5 mmol) and dimethylaminopyridine (66 mg; 0.54 mmol) at 10-15° C. for 3 hours. The reaction wasthen filtered to remove solids and the filtrate was washed with water(10 mL), dried with anhydrous sodium sulfate and concentrated. The crudeproduct was purified by column chromatography using silica gel(petroleum ether/ethyl acetate 25/1) to give 1.8 g (59%) of(S)—(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-1-oxohept-4-en-3-yl2-((tert-butoxycarbonyl)amino)-3-methylbutanoate as a yellow, foamysolid.

¹H NMR: (CDCl₃, 400 MHz): δ 7.37-7.27 (m, 5H), 5.93-5.83 (m, 2H), 5.62(dd, J=15.8, 8.6 Hz, 1H), 5.37 (m, 1H), 5.04 (d, J=9.1 Hz, 1H), 4.19(dd, J=9.0, 4.5 Hz, 1H), 3.68 (dd, J=17.4, 8.6 Hz, 1H), 3.57 (dd,J=18.8, 4.7 Hz, 1H), 3.54 (t, J=6.8 Hz, 2H), 3.45 (dd, J=11.5, 7.2 Hz,1H), 3.21 (dd, J=13.1, 3.5 Hz, 1H), 3.02 (dd, J=13.0, 10.7 Hz, 1H), 2.89(d, J=11.6 Hz, 1H), 2.51 (q, J=6.8 Hz, 2H), 2.12 (m, 1H), 1.42 (s, 9H),0.95 (d, J=6.8 Hz, 3H), 0.85 (d, J=6.9 Hz, 3H).

Example 9: Preparation of(S)—(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-1-oxohept-4-en-3-yl2-((tert-butoxycarbonyl)amino)-3-methylbutanoate (Compound XVI) fromtert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)thiazole-4-carboxylate(Compound VIII) and tert-butyl 2-(aminomethyl)thiazole-4-carboxylate(Compound XV)

To a solution of(S)—(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-1-oxohept-4-en-3-yl2-((tert-butoxycarbonyl)amino)-3-methylbutanoate (0.5 g, 0.88 mmol) inDMF (5 mL), was added tert-butyl 2-(aminomethyl)thiazole-4-carboxylatehydrochloride (0.19 g, 0.88 mmol) and diisopropylethyl amine (340 mg,2.64 mmol), and the resulting mixture was stirred at 10-15° C. for 3hours. H₂O (20 mL) was then added and the resulting mixture wasextracted with ethyl acetate (50 mL). The organic phase was separated,dried with anhydrous sodium sulfate and concentrated. The crude productwas purified by column chromatography using silica gel (petroleumether/ethyl acetate 2/1) to give 0.40 g (80%) of tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)thiazole-4-carboxylateas a foamy, white solid. ¹H NMR: (CDCl₃, 400 MHz): δ 7.98 (s, 1H), 7.48(bs, 1H), 7.13 (bs, 1H), 5.80 (m, 1H), 5.62 (m, 2H), 4.97 (s, 1H), 4.75(d, J=5.9 Hz, 2H), 4.24 (t, J=6.7 Hz, 1H), 3.49 (t, J=6.7 Hz, 2H), 2.65(d, J=4.9 Hz, 2H), 2.47 (q, J=6.7 Hz, 2H), 2.08 (m, 1H) 1.57 (s, 9H),1.41 (s, 9H), 0.92 (d, J=6.8 Hz, 3H), 0.87 (d, J=6.8 Hz, 3H).

Example 10: Preparation of tert-butyl2-((amino)methyl)thiazole-4-carboxylate (Compound XV) from tert-butyl2-(((tert-butoxycarbonyl)amino)methyl)thiazole-4-carboxylate (CompoundXIV)

To a solution of 20.0 g (0.064 mol) of tert-butyl2-(((tert-butoxycarbonyl)amino)methyl)thiazole-4-carboxylate in dioxane(160 ml) at room temperature was added 120 ml 4M HCl in dioxane. Afterstirring overnight at room temperature, 160 ml petroleum ether was addedand the resulting precipitate was filtered, washed with heptane anddried under vacuum to give 15.9 g (100%) of tert-butyl2-(aminomethyl)thiazole-4-carboxylate hydrochloride which was usedwithout further purification. ¹H NMR: (CD₃OD, 400 MHz): δ 8.20 (s, 9H),4.84 (bs, 1H), 4.13 (s, 2H), 1.61 (s, 9H).

Example 11: Preparation of tert-butyl2-(((tert-butoxycarbonyl)amino)methyl)thiazole-4-carboxylate (CompoundXIV) from tert-butyl bromopyruvate (Compound XII) and tert-butyl(2-amino-2-thioxoethyl)carbamate (Compound XIII)

28.0 g (0.126 mol) of ethyl bromopyruvate and 25.0 g (0.131 mol) oftert-butyl (2-amino-2-thioxoethyl)carbamate were combined in isopropanol(250 ml). The mixture was stirred for 16 h. at which time 28.6 g of 20%aqueous sodium hydroxide was added followed by 500 ml H₂O. The productwas extracted with EA (500 ml, 250 ml). The organic layer was washedwith saturated sodium chloride solution, dried with anhydrous sodiumsulfate, filtered and dried. Flash chromatography using silica gel(petroleum ether/ethyl acetate 85/15) gave 32 g, 72%) of tert-butyl2-(((tert-butoxycarbonyl)amino)methyl)thiazole-4-carboxylate as a whitesolid. ¹H NMR: (CD₂C₂, 400 MHz): δ 7.92 (s, 1H), 5.23 (bs, 1H), 1.37 (s,9H), 1.53 (s, 9H).

Example 12: Preparation of(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(Compound XI) from(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(Compound VI-B) and tert-butyl 2-(aminomethyl)thiazole-4-carboxylate(Compound XV)

To a solution of(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(10.0 g, 0.027 mol) in dichloromethane (80 mL) was added tert-butyl2-(aminomethyl)thiazole-4-carboxylate (8.0 g, 0.032 mol).Diisopropylethyl amine (9.0 g, 0.07 mol) was then added dropwise whilemaintaining the temperature between 20-30° C. After the addition, theresulting solution was stirred at room temperature for 8 hours, at whichtime water (80 mL) was added. The layers were separated, and the aqueouslayer was extracted once with dichloromethane (40 mL). The combinedorganic layers were washed with brine, dried with anhydrous sodiumsulfate and concentrated. The residue was dissolved in ethyl acetate (20mL) and the precipitated solid was filtered. The mother liquor wasconcentrated, the residue was dissolved in ethyl acetate (20 mL), andthe precipitated solid was filtered. The combined solids were driedunder vacuum to give 7.8 g (77%) of (S,E)-tert-butyl2-((7-chloro-3-hydroxyhept-4-enamido)methyl)thiazole-4-carboxylate. Anadditional 1.3 g of product was obtained by concentrating the finalmother liquor and purifying the residue by flash chromatography withsilica gel (petroleum ether/dichloromethane: 80/20˜50/50). ¹H NMR:(CDCl₃, 400 MHz): δ 7.98 (s, 1H), 7.38 (bt, J=5.7 Hz, 1H), 5.72 (dt,J=15.6, 5.6 Hz, 1H), 5.61 (dd, J=15, 6, 5.8 Hz, 1H), 4.75 (dq, J=15.6,6.0 Hz, 2H), 4.54 (bs, 1H), 3.93 (s, 1H), 3.50 (t, J=6.8 Hz, 2H),2.57-2.43 (m, 4H), 1.57 (s, 9H).

Example 13: Preparation of(S)—(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-1-oxohept-4-en-3-yl2-((tert-butoxycarbonyl)amino)-3-methylbutanoate (Compound XVI) from(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(Compound XI) and 2-((tert-butoxycarbonyl)amino)acetic acid (CompoundVII)

(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(17.0 g, 0.045 mol) and(S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (11.8, 0.045mol) were dissolved in dichloromethane (250 mL), the mixture was cooledto 0-5° C. and dimethylaminopyridine (0.55 g, 4.5 mmol) and1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (17.3 g, 0.054 mol) wereadded. The reaction was stirred at 0-5° C. for 20 hours at which timedichloromethane (100 mL) water (200 mL) were added. The organic layerwas separated and washed with water (150 mL). The organic layer wasdried with anhydrous sodium sulfate and concentrated to give 25.8 g(100%) of(S)—(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-1-oxohept-4-en-3-yl2-((tert-butoxycarbonyl)amino)-3-methylbutanoate as a foamy solid whichwas used without further purification. ¹H NMR: (CD₂Cl₂, 400 MHz): δ 7.98(s, 1H), 7.49 (bs, 1H), 7.13 (bs, 1H), 5.78 (m, 1H), 5.65 (m, 1H), 4.98(s, 1H), 4.75 (d, J=2.8 Hz, 2H), 4.25 (t. J=6.4 Hz, 1H), 3.49 (t, J=6.8Hz, 2H), 2.65 (d, J=6.8 Hz, 2H), 2.47 (q, J=6.4 Hz, 4H), 1.57 (s, 9H),1.41 (s, 9H), 0.92 (d, J=6.8 Hz, 3H) 0.88 (d, J=6.8 Hz, 3H).

Example 14a: Preparation of(S,E)-7-chloro-3-hydroxy-1-((R)-4-isopropyl-2-thioxothiazolidin-3-yl)hept-4-en-1-one(Compound VI-A-1, Table 2) from (E)-5-chloropent-2-enal (Compound IV)and (R)-1-(4-isopropyl-2-thioxothiazolidin-3-yl)ethanone (Compound V-A;Table 2) (from Scheme 3)

(R)-1-(4-isopropyl-2-thioxothiazolidin-3-yl)ethanone (4.0 g, 19.6 mmol)was dissolved in dichloromethane (150 ml) and cooled to −40° C. TiCl₄(6.0 g, 31.62 mmol) was added while maintaining the reaction temperaturebelow −40° C. After stirring for 1 h, diisopropylethyl amine (4.1 g,31.62 mmol) was added dropwise while maintaining the reactiontemperature between −40 to −50° C. After the addition, the mixture wasstirred at −40° C. for 2 hours at which time, the reaction was cooled to−78° C. and (E)-5-chloropent-2-enal (2.21 g, 18.6 mmol) indichloromethane (10 ml) was added slowly dropwise while maintaining thereaction temperature below −65° C. After the addition, the resultingmixture was stirred at −70 to −65° C. for 1 hour and then poured into amixture of saturated aqueous ammonium chloride solution (100 ml) andsaturated aqueous sodium chloride (100 ml). The resulting mixture wasextracted twice with dichloromethane (400 ml) and the combined organiclayers were washed with saturated aqueous sodium chloride solution (100mL) and concentrated to dryness. Purification by column chromatographygave 4.8 g (80%) of(S,E)-7-chloro-3-hydroxy-1-((R)-4-isopropyl-2-thioxothiazolidin-3-yl)hept-4-en-1-one(Compound VI-A, Table 2). ¹H NMR: (CDCl₃, 400 MHz): δ 5.76 (dt, J=15.6,6.5 Hz, 1H), 5.66 (dd, J=15.6, 5.6 Hz, 1H), 5.15 (t, J=7.0 Hz, 1H), 4.65(m, 1H), 3.64 (dd, J=17.6, 3.0 Hz, 1H), 3.56-3.50 (m, 3H), 3.29 (dd,J=17.7, 8.8 Hz, 1H) 3.03 (d, J=11.5 Hz, 1H), 2.90 (bs, 1H), 2.51 (q,J=6.8 Hz, 2H), 2.36 (m, 1H), 1.06 (d, J=6.8 Hz, 3H), 0.98 (d, J=6.9 Hz,3H).

Example 14b: Preparation(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(Compound VI-B-1; Table 2) from (E)-5-chloropent-2-enal (Compound IV)and (R)-1-(4-benzyl-2-thioxothiazolidin-3-yl)ethanone (Compound V-B)(from Scheme 3)

(R)-1-(4-benzyl-2-thioxothiazolidin-3-yl)ethanone (36 g, 0.143 mol) wasdissolved in dichloromethane (1 L) and cooled to −40° C. TiCl₄ (29 g,0.153 mol) was added while maintaining the reaction temperature below−40° C. After stirring for 1 h, diisopropylethyl amine (20 g, 0.153 mol)was added dropwise while maintaining the reaction temperature between−40 to −50° C. After the addition, the mixture was stirred at −40° C.for 2 hours at which time, the reaction was cooled to −78° C. and(E)-5-chloropent-2-enal (10.0 g, 0.084 mol) in dichloromethane (40 ml)was added slowly dropwise while maintaining the reaction temperaturebelow −65° C. After the addition, the resulting mixture was stirred at−70 to −65° C. for 1 hour and then poured into a mixture of saturatedaqueous ammonium chloride solution (500 ml) and saturated aqueous sodiumchloride (500 ml). The resulting mixture was extracted twice withdichloromethane (400 ml) and the combined organic layers were washedwith saturated aqueous sodium chloride solution (500 mL) andconcentrated to dryness. Ethyl acetate (50 mL) was added to the residue,followed by a slow addition of petroleum ether (150 mL). Theprecipitated solid was collected by filtration and the mother liquor wasconcentrated. Ethyl acetate (50 mL) was added to the residue, followedby a slow addition of petroleum ether (150 mL). The precipitated solidwas collected by filtration, combined with the first lot of collectedsolid and dried under vacuum to give 22 g (71%) of(S,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(Compound VI-B-1, Table 2) which contained 2% of the minor diastereomer(R,E)-1-((R)-4-benzyl-2-thioxothiazolidin-3-yl)-7-chloro-3-hydroxyhept-4-en-1-one(Compound VI-B, Table 2). ¹H NMR: (CDCl₃, 400 MHz): δ 7.38-7.27 (m, 5H),5.78 (dt, 1H, J=16.1, 6.3 Hz, 1H), 5.69 (dd, J=15.5, 5.6 Hz, 1H), 5.39(ddd, J=10.4, 6.9, 3.8 Hz, 1H), 4.68 (m, 1H), 3.65 (dd, J=17.7, 2.9 Hz,1H), 3.57 (t, J=6.8 Hz, 2H), 3.41 (dd, J=11.5, 7.2 Hz, 1H), 3.31 (dd,J=17.7, 8.9 Hz, 1H), 3.23 (dd, J=13.2, 3.9 Hz, 1H), 3.05 (dd, J=13.2,10.5 Hz, 1H), 2.91 (d, J=11.6 Hz, 1H), 2.81 (d, J=4.4 Hz, 1H), 2.54 (q,J=6.7 Hz, 2H).

Example 15: Preparation of (E)-5-chloropent-2-enal (Compound IV) from4-chloro-but-1-ene (Compound I) and crotonaldehyde, (Compound II)

4-chloro-but-1-ene (20 g, 0.22 mol), crotonaldehyde (23 g, 1.5 eq) andCuI (2.5 g, 0.06 eq) were combined in dichloromethane (400 mL) and(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(tricyclohexylphosphine)ruthenium)(Grubbs 2nd generation olefin metathesis catalyst) (0.011 mol, 0.93 g,0.5 mol %) was added in one portion while purging with nitrogen. Themixture was heated to reflux at 40° C. for 16 hours with stirring atwhich time analysis of the reaction by 1HNMR indicated 65-70%conversion. The reaction mixture was then cooled, filtered, andconcentrated. The residue was dissolved in dichloromethane (150 ml) andthe dichloromethane was evaporated under vacuum to remove unreactedstarting material. This was repeated 4 times. The product thus producedwas used in subsequent Aldol condensation reactions without any furtherpurification. An analytically pure sample was obtained via flashchromatography using silica gel (petroleum ether/dichloromethane 50/50).¹H NMR: (CD₂Cl₂, 400 MHz): δ 9.51 (d, J=8.0 Hz, 1H), 6.82 (dt, J=15.6,6.8 Hz, 1H), 6.16 (ddt, J=15.6, 6.8, 1.6 Hz, 1H), 3.68 (t, J=6.4 Hz,2H), 2.78 (qd, J=5.2, 1.2 Hz, 2H).

Example 16: Preparation of (E)-5-chloropent-2-en-1-ol (Compound III)from 4-chloro-but-1-ene (Compound I) and (E)-but-2-ene-1,4-diol,(Compound II from Scheme 1)

4-chloro-but-1-ene (3.4 g, 0.037 mol), (E)-but-2-ene-1,4-diol (5.0 g,0.055 mol) and CuI (0.42 g, 2.22 mmol) were combined in dichloromethane(70 mL) and(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(tricyclohexylphosphine)rutheniumGrubbs 2nd generation olefin metathesis catalyst) (0.185 mmol, 0.157 g)was added in one portion while purging with nitrogen. The mixture washeated to reflux at 40° C. for 16 hours with stirring at which timeanalysis of the reaction by 1HNMR indicated 82% conversion. The reactionmixture was then cooled, filtered, and concentrated to give crude(E)-5-chloropent-2-en-1-ol which was used directly in the next reaction.¹H NMR: (DMSO-d₆, 400 MHz): δ 5.69-5.52 (m, 2H), 4.70 (t, J=5.4 Hz, 1H),3.91 (m, 2H), 3.64 (t, J=6.8 Hz, 2H), 2.54 (m, 2H).

Example 17: Preparation of (E)-5-chloropent-2-en-1-al from (Compound IV)from (E)-5-chloropent-2-en-1-ol (Compound III)

To a solution of (E)-5-chloropent-2-en-1-ol (0.40 g, 3.33 mmol) indichloromethane (5 mL) was added manganese dioxide (0.87 g, 10.0 mmol)and the resulting mixture was stirred at room temperature for 20 hours.The mixture was then filtered and concentrated to give of(E)-5-chloropent-2-en-1-al (90% conversion based on ¹H NMR). ¹H NMR:(CD₂Cl₂, 400 MHz): δ 9.51 (d, J=8.0 Hz, 1H), 6.82 (dt, J=15.6, 6.8 Hz,1H), 6.16 (ddt, J=15.6, 6.8, 1.6 Hz, 1H), 3.68 (t, J=6.4 Hz, 2H), 2.78(qd, J=5.2, 1.2 Hz, 2H).

Example 18: Preparation ofS-((E)-4-((5R,8S,11S)-8-isopropyl-5-methyl-6,9,13-trioxo-10-oxa-3,17-dithia-7,14,19,20-tetraazatricyclo[14.2.1.12,5]icosa-1(18),2(20),16(19)-trien-11-yl)but-3-en-1-yl)octanethioate (Largazole, a compound of Formula (2)) from(5R,8S,11S)-11-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-5-methyl-10-oxa-3,17-dithia-7,14,19,20-tetraazatricyclo[14.2.1.12,5]icosa-1(18),2(20),16(19)-triene-6,9,13-trione(Compound XXIX)

(5R,8S,11S)-11-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-5-methyl-10-oxa-3,17-dithia-7,14,19,20-tetraazatricyclo[14.2.1.12,5]icosa-1(18),2(20),16(19)-triene-6,9,13-trione(Compound XXIX) (0.23 g, 0.46 mmol), octanethioic S-acid (0.44 g, 2.75mmol), potassium carbonate (0.40 g, 2.90 mmol) and potassium iodide(0.067 g, 0.41 mmol) were dissolved in acetonitrile (20 mL) at roomtemperature. The mixture was stirred at room temperature under nitrogenfor 16 hours. The mixture was filtered, concentrated and purified bypreparative silica gel chromatography (dichloromethane/methanol 50/1) togive 0.12 g, (42%) ofS-((E)-4-((5R,8S,11S)-8-isopropyl-5-methyl-6,9,13-trioxo-10-oxa-3,17-dithia-7,14,19,20-tetraazatricyclo[14.2.1.12,5]icosa-1(18),2(20),16(19)-trien-11-yl)but-3-en-1-yl)octanethioate as a white solid. 1H NMR: (CDCl₃, 400 MHz): δ 7.76 (s,1H), 7.16 (d, J=9.4 Hz, 1H), 6.43 (d, J=10.4 Hz, 1H), 5.83 (dt, J=15.8,7.3 Hz, 1H), 5.66 (m, 1H), 5.51 (dd, J=15.5, 6.9 Hz, 1H), 5.29 (dd,J=17.7, 9.3 Hz, 1H), 4.60 (dd, J=9.4, 3.3 Hz, 1H), 4.27 (dd, J=17.6, 3.0Hz, 1H), 4.04 (d, J=11.4 Hz, 1H), 3.28 (d, J=11.4 Hz, 1H), 2.90 (t,J=7.2 Hz, 2H), 2.87 (dd, J=16.4, 10.4 Hz, 1H), 2.68 (dd, J=16.3, 2.7 Hz,1H), 2.53 (t, J=7.5 Hz, 1H), 2.31 (q, J=7.0 Hz, 2H), 2.11 (m, 1H), 1.87(s, 3H), 1.62 (m, 2H), 1.27 (m, 8H), 0.87 (m, 3H), 0.69 (d, J=6.7 Hz,3H), 0.51 (d, J=6.8 Hz, 3H).

Example 19: Preparation of(5R,8S,11S)-11-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-5-methyl-10-oxa-3,17-dithia-7,14,19,20-tetraazatricyclo[14.2.1.12,5]icosa-1(18),2(20),16(19)-triene-6,9,13-trione(Compound XXIX) from(R)-2′-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)-4-methyl-4,5-dihydro-[2,4′-bithiazole]-4-carboxylicacid (Compound XXVII)

(R)-2′-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)-4-methyl-4,5-dihydro-[2,4′-bithiazole]-4-carboxylicacid (Compound XXVII) (1.5 g, 2.4 mmol) was dissolved in dichloromethane(20 ml), and trifluoroacetic acid (2.9 g, 25.4 mmol) was added whilestirring at 20-25° C. After stirring the resulting mixture at 20-25° C.for 3 hours, an additional aliquot of trifluoroacetic acid (0.80 g, 7.0mmol) was added and the resulting mixture was stirred for an additional3.5 hours at which time the reaction was determined to be complete byHPLC. To the crude reaction mixture containing(R)-2′-(((S,E)-3-(((S)-2-amino-3-methylbutanoyl)oxy)-7-chlorohept-4-enamido)methyl)-4-methyl-4,5-dihydro-[2,4′-bithiazole]-4-carboxylicacid trifluoroacetic acid salt (Compound XXVIII) was addeddiisopropylethyl amine (4.7 g, 41.2 mmol). The resulting mixture wasthen added slowly dropwise over a 5-6 hour period to a preformedsolution of HATU (2.9 g, 7.63 mmol) dissolved in acetonitrile (50 mL) at0˜5° C. After the addition, the mixture was stirred at 0˜5° C. for anadditional 2 hours at which time water (100 mL) was added. After layerseparation, the aqueous layer was extracted twice with ethyl acetate (50mL), and the combined organic layers were washed with brine, dried withanhydrous sodium sulfate and concentrated. Flash chromatography withsilica gel (dichloromethane/methanol 40/1) provided(5R,8S,11S)-11-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-5-methyl-10-oxa-3,17-dithia-7,14,19,20-tetraazatricyclo[14.2.1.12,5]icosa-1(18),2(20),16(19)-triene-6,9,13-trione(0.26 g) as a white solid (23% overall from Compound XXVII). ¹H NMR:(CDCl₃, 400 MHz): δ 7.76 (s, 1H), 7.19 (d, J=7.4 Hz, 1H), 6.49 (d, J=8.6Hz, 1H), 5.89 (dt, J=15.7, 7.3 Hz, 1H), 5.70 (m, 1H), 5.60 (dd, J=15.6,6.5 Hz, 1H), 5.28 (dd, J=17.0, 9.1 Hz, 1H), 4.61 (dd, J=9.0, 3.5 Hz,1H), 4.27 (dd, J=17.5, 2.9 Hz, 1H), 4.04 (d, J=11.2 Hz, 1H), 3.54 (t,J=6.6 Hz, 2H), 3.28 (d, J=11.3 Hz, 1H), 2.85 (m, 1H), 2.72 (dd, J=16.3,2.7 Hz, 1H), 2.51 (q, J=6.7 Hz, 2H), 2.10 (m, 1H), 1.86 (s, 3H), 0.70(d, J=6.9 Hz, 3H), 0.53 (d, J=6.8 Hz, 3H).

Example 20: Preparation of(R)-2′-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)-4-methyl-4,5-dihydro-[2,4′-bithiazole]-4-carboxylicacid (Compound XXVII) from tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)thiazole-4-carboxylate(Compound VIII) and(R)-2′-(aminomethyl)-4-methyl-4,5-dihydro-[2,4′-bithiazole]-4-carboxylicacid (Compound XXVI)

Tert-butyl2-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)thiazole-4-carboxylate(Compound VIII) (1.0 g, 1.8 mmol) was added to a preformed solution of(R)-2′-(aminomethyl)-4-methyl-4,5-dihydro-[2,4′-bithiazole]-4-carboxylicacid triflouroacetic acid salt (Compound XXVI) (0.51 g, 2.0 mmol)(prepared via modification of the method described in: Xiao, Q. et al.,Journal of Asian Natural Products Research, (2010), 12:11, 940) anddiisopropylethylamine (2.5 g, 0.025 mmol) in dichloromethane (10 mL).After stirring at 25° C. for 16 hours, H₂O (20 mL) was added and thelayers were separated. The aqueous phase was extracted withdichloromethane (20 mL) once, and the combined organic phases were driedwith anhydrous sodium sulfate, filtered and concentrated. Purificationby flash chromatography (dichloromethane/MeOH=40:1→10:1), afforded 1.6 g(88%) of(R)-2′-((5S,8S)-5-((E)-4-chlorobut-1-en-1-yl)-8-isopropyl-12,12-dimethyl-3,7,10-trioxo-6,11-dioxa-2,9-diazatridecyl)-4-methyl-4,5-dihydro-[2,4′-bithiazole]-4-carboxylicacid as a foam. Mass Spec (m/z): 617.9.

All published documents (e.g. patents, journal articles, books) citedherein are incorporated by reference in their entireties.

What is claimed is:
 1. A thioester compound of Formula (XXV)

or a pharmaceutically acceptable salt thereof, wherein: R₁ and R₂ are H;R₃ and R₄ are CH₃; R₅ is H and R₆ is isopropyl, or R₅ is isopropyl andR₆ is H; R₁₃ is H and R₁₄ is C₁-C₁₀ alkyl, or R₁₃ is C₁-C₁₀ alkyl andR₁₄ is H.
 2. A method of treating disorders associated with inhibitionof histone deacetylase, comprising administration of a compoundaccording to claim
 1. 3. The method according to claim 2, wherein thedisorder is selected from the group consisting of cancer, inflammatorydiseases, autoimmune diseases, allergic diseases and diseases of thecentral nervous system.
 4. A method of treating disorders associatedwith inhibition of histone deacetylase, comprising administration of athioester compound having the following formula

for a pharmaceutically acceptable salt thereof.
 5. The method accordingto claim 4, wherein the disorder is selected from the group consistingof cancer, inflammatory diseases, autoimmune diseases, allergic diseasesand diseases of the central nervous system.
 6. A method for preparingthe thioester of Formula (XXV) according to claim 1, comprising:treating a compound of Compound (XX)

where R₁, R₂, R₃, R₄, R₅ and R₆ are as defined in claim 1, with acompound of Formula (XXIII)

where R₁₃ and R₁₄ are as defined in claim 1, to provide a compound ofFormula (XXIV)

followed by deprotection of the compound of Formula XXIV to providecompound of Formula (XXV) or a pharmaceutically acceptable salt thereof.7. The method according to claim 6, wherein the compound of Formula(XXV) has the following formula:

or a pharmaceutically acceptable salt thereof.
 8. The method accordingto claim 7, wherein the pharmaceutically acceptable salt is a chloridesalt.
 9. The method according to claim 7, wherein the pharmaceuticallyacceptable salt is a sulfonate salt.